Prevalence, Bacterial Etiology, and Risk Factors of Clinical and Subclinical Mastitis in Dromedary Camels (Camelus dromedarius) Across Pastoral and Peri-Urban Production Systems in Somalia

Prevalence, Bacterial Etiology, and Risk Factors of Clinical and Subclinical Mastitis in Dromedary Camels (Camelus dromedarius) Across Pastoral and Peri-Urban Production Systems in Somalia | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Prevalence, Bacterial Etiology, and Risk Factors of Clinical and Subclinical Mastitis in Dromedary Camels (Camelus dromedarius) Across Pastoral and Peri-Urban Production Systems in Somalia Shafii Abdullahi Mohamed, Daha Hussein Mumin, Anfac Abdullahu Guled, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9233776/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Mastitis is a major constraint to camel milk productivity, udder health, and milk safety in Somali pastoral and emerging peri-urban dairy systems, yet comparative epidemiological data across these systems remain scarce. This cross-sectional study investigated the prevalence, bacterial etiology, and risk factors of mastitis in lactating dromedary camels in Somalia, and examined the relationship between California Mastitis Test (CMT) score and somatic cell count (SCC), together with antibiotic residues in a subset of milk samples. Between August 2024 and January 2026, 384 lactating camels from pastoral and peri-urban production systems were enrolled, yielding 1,536 quarter milk samples. Clinical mastitis was assessed by udder examination, subclinical mastitis by CMT, SCC was measured in 1,419 quarter samples, and bacteriological culture was performed on quarter milk samples. At camel level, 48.4% had clinical mastitis, 91.7% had at least one CMT-positive quarter, and 68.2% had at least one culture-positive quarter. At quarter level, the prevalence of clinical mastitis, CMT positivity, and culture positivity was 16.5%, 47.8%, and 24.6%, respectively. Coagulase-negative staphylococci were the most frequent isolates (28.0%), followed by Staphylococcus aureus (21.7%), Escherichia coli (13.0%), Streptococcus agalactiae (10.8%), and Streptococcus uberis (9.8%). Median SCC increased progressively from 99,548 cells/mL in CMT score 0 quarters to 2,542,414 cells/mL in CMT score 3 quarters (p < 0.001). In multivariable generalized estimating equation analysis, peri-urban production system (AOR 1.54, 95% CI 1.23–1.93), mild teat lesions (AOR 1.61, 95% CI 1.18–2.19), and severe teat lesions (AOR 2.04, 95% CI 1.29–3.24) were significantly associated with quarter-level CMT positivity. Antibiotic residue screening identified confirmed positives in a subset of milk samples, with beta-lactams predominating. These findings show that mastitis is widespread in Somali camel dairying and is shaped by both bacterial infection and modifiable management-related factors, particularly under peri-urban conditions. Improved udder-health surveillance, teat-health management, and prudent antimicrobial-use practices are needed to reduce disease burden and improve camel milk safety. camel mastitis Camelus dromedarius pastoral systems peri-urban dairy somatic cell count bacterial pathogens Somalia Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Somalia is one of the world’s major livestock-dependent countries, where pastoral and agro-pastoral systems operate under harsh dryland conditions and milk production remains central to food security and rural livelihoods 1 – 4 . Within these systems, dromedary camels ( Camelus dromedarius ) are especially important because they are well adapted to drought, high temperatures, erratic feed resources, and long-distance mobility, and can maintain milk production under conditions that constrain other dairy species 1 , 3 , 5 . In Somalia and across the wider Horn of Africa, camel milk supports household nutrition, income generation, and livelihood resilience, while commercialization and urban demand are increasing the importance of camel dairying in both pastoral and peri-urban settings 6 , 7 . However, expansion of the camel milk sector has also intensified concerns around hygienic milking, veterinary support, informal marketing, and milk safety, particularly where cold-chain infrastructure and quality assurance remain limited 2 , 3 , 8 , 9 . Within this context, udder health is a key determinant of both productivity and milk safety. Mastitis, defined as inflammation of the mammary gland, is one of the most important health constraints in dairy animals and is increasingly recognized as a major problem in camels 10 – 12 . It occurs in both clinical and subclinical forms. Clinical mastitis is characterized by visible abnormalities of the udder or milk, whereas subclinical mastitis is not readily apparent without screening and may persist while reducing milk yield, altering milk composition, and facilitating continued pathogen shedding 10 , 12 . In camel production systems, where hand-milking, calf-at-foot management, limited routine laboratory testing, and informal milk marketing are common, subclinical infection may remain undetected while still carrying biological, economic, and public-health consequences 11 – 13 . Camel mastitis is important not only because of milk loss, but also because intramammary infection affects milk quality and safety. Mastitis has been associated with elevated somatic cell counts (SCC), altered physicochemical characteristics of milk, and recovery of important bacterial pathogens 6 , 12 . Studies in camel dairies have shown that SCC varies with udder health status and management conditions, supporting its value as an indicator of mammary inflammation and milk-quality deterioration 6 , 7 , 14 . A wide range of bacterial pathogens has been implicated, including Staphylococcus aureus , coagulase-negative staphylococci, streptococci, Escherichia coli , and other contagious or environmental organisms, although the relative importance of these agents varies across production systems and settings 5 , 9 , 12 , 15 – 18 . This mixed contagious-environmental pattern is epidemiologically important because it implies that effective control depends on both improved milking hygiene and broader management of environmental exposure 11 , 12 . Milk-safety concerns are especially relevant in camel systems because milk is often consumed raw or only minimally processed in pastoral and peri-urban settings 8 , 19 . Under these conditions, mastitis may increase the risk of bacterial contamination, while treatment practices can also introduce antimicrobial residues when withdrawal periods are poorly understood or not observed 8 , 19 . Informal camel milk value chains in East Africa have repeatedly been shown to contain hygiene gaps from production to market 8 , 9 , and emerging camel-specific evidence suggests that some antibiotics may persist in milk longer than expected, underscoring the need for species-specific milk-safety data rather than simple extrapolation from cattle 19 . The epidemiology of camel mastitis is shaped by interacting host, environmental, and management-related factors. Previous studies have identified associations with age, parity, stage of lactation, tick infestation, udder and teat lesions, milking hygiene, and production system 5 , 9 , 15 , 16 , 18 . Teat and udder lesions are particularly important because they compromise the natural barrier to infection, while production-system differences may influence stocking density, handling intensity, veterinary access, and pathogen transmission dynamics 5 , 15 , 18 . Diagnostic studies in dromedaries also support the use of combined screening approaches: California Mastitis Test (CMT), SCC, and bacteriological examination show positive relationships, although threshold interpretation remains partly context-specific in camels 11 , 13 , 14 . In field settings where laboratory capacity may be constrained, such tools are especially relevant for routine udder-health surveillance. Despite the nutritional and economic importance of camels in Somalia, integrated epidemiological evidence on camel mastitis in the country remains limited. Available studies from neighboring regions indicate that mastitis is common, multifactorial, and influenced by production environment, but Somali data remain scarce, particularly for studies that jointly assess clinical mastitis, subclinical inflammation, bacteriological positivity, and residue-related milk-safety concerns across contrasting production systems 5 , 15 , 16 , 18 . This knowledge gap is important because pastoral and peri-urban camel dairying differ markedly in herd mobility, market integration, handling intensity, and management conditions, all of which may shape disease risk and milk quality 2 , 3 , 8 . Therefore, the present study aimed to estimate the prevalence of clinical mastitis, CMT positivity, and bacteriological culture positivity at camel and quarter levels in lactating dromedary camels in Somalia, identify associated risk factors, characterize the major bacterial isolates, and assess antibiotic residues in a subset of milk samples. Methods Study design and setting This cross-sectional study was conducted to estimate the prevalence of clinical mastitis, subclinical mastitis, and bacteriological culture positivity in lactating dromedary camels in Somalia; to identify associated risk factors; and to characterize major bacterial isolates and antibiotic residue occurrence in milk samples. The study was carried out between August 2024 and January 2026 in six districts representing two camel production systems: pastoral (Afgooye, Walanweyn, and Yaaqbariweyne) and peri-urban (Dharkenley, Garasbaley, and Kaxda). Study population and sample size The study population comprised lactating one-humped camels ( Camelus dromedarius ) managed under the selected pastoral and peri-urban production systems. Camels were eligible if they were lactating, had four accessible udder quarters, and could be safely restrained for clinical examination and milk sampling. Herds and individual camels were selected using simple random sampling within the study districts. Sample size was determined using Cochran’s formula for prevalence studies: $$\:n=\frac{{Z}^{2}p\left(1-p\right)}{{d}^{2}}$$ where n is the required sample size, Z is the standard normal deviate at the 95% confidence level, p is the expected prevalence, and d is the desired precision. Assuming an expected prevalence of 50% and a precision of 5%, the minimum required sample size was 384 camels 20 . Accordingly, 384 lactating camels were enrolled, yielding 1,536 quarter-level observations. Clinical examination and milk sampling Field data were recorded using a structured case-record form. Camel-level variables included district, production system, age group, parity, lactation stage, body condition score, breed or ecotype, and recent antibiotic exposure when treatment history was available. Before milk collection, each camel underwent clinical examination of the udder and teats. Quarter-level observations included quarter position, teat lesion severity, and tick severity. Milk samples were collected aseptically from all four udder quarters (left fore, right fore, left hind, and right hind). Teat ends were cleaned and disinfected with 70% alcohol, the first streams of milk were discarded, and approximately 10–15 mL of milk was collected into sterile labelled tubes. Samples were kept chilled during handling and transport to the Somali National University Diagnostic Veterinary Laboratory for analysis. California Mastitis Test Subclinical mastitis screening was performed at the Somali National University Diagnostic Veterinary Laboratory using the California Mastitis Test (CMT), following the standard method described by 21 . Approximately 2 mL of milk was mixed with an equal volume of commercial CMT reagent in a paddle cup and rotated gently for 10–15 s. Reactions were scored as 0, Trace, 1, 2, or 3 according to gel formation. Quarters with CMT scores of 1 or greater were classified as positive, whereas Trace was considered negative, in line with established interpretation criteria 21 – 23 . The reagent used was WIKO® California Mastitis Test (Gluetec Industrial Adhesives, Germany). Somatic cell count Somatic cell count (SCC) was measured for 1,419 quarter milk samples at the Somali National University Diagnostic Veterinary Laboratory using a Fossomatic™ 7 somatic cell counter (FOSS, Hillerød, Denmark), based on the fluoro-opto-electronic method. SCC was used as an indicator of mammary inflammation and evaluated in relation to CMT score categories 24 , 25 . Bacteriological analysis and isolate identification Bacteriological culture and isolate identification were performed at the Somali National University Diagnostic Veterinary Laboratory. Milk aliquots were cultured on 5% sheep blood agar and MacConkey agar and incubated aerobically at 35–37°C. Plates were examined after 18–24 h and, when necessary, again at 48 h. Bacterial isolates were characterized on the basis of colony morphology, haemolysis, lactose fermentation, Gram reaction, and routine biochemical characteristics. Samples showing mixed, non-interpretable growth of unrelated colony types were classified as contaminated rather than as true intramammary infection. Presumptive identification was further supported by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), with targeted molecular confirmation performed for selected isolates according to laboratory workflow. Antibiotic residue screening Antibiotic residue screening was conducted at the Somali National University Diagnostic Veterinary Laboratory on a subset of milk samples. Of 384 samples available for this component, 360 were screened using Delvotest® (dsm-firmenich, Delft, the Netherlands) as a broad-spectrum microbial inhibitor test. Samples interpreted as positive or unclear were subsequently analysed using TriSensor® (Unisensor, Seraing, Belgium), a rapid dipstick assay for the detection of beta-lactams, sulfonamides, and tetracyclines in milk. Outcome definitions Outcome definitions The primary outcomes were clinical mastitis, quarter-level CMT positivity, and quarter-level bacteriological culture positivity. Clinical mastitis was defined as the presence of visible abnormalities in the udder or milk detected during clinical examination. A quarter was classified as CMT-positive if the score was at least 1. A quarter was classified as culture-positive when bacterial growth was considered consistent with intramammary infection based on culture interpretation criteria. At camel level, an animal was classified as positive if at least one quarter met the relevant outcome definition. Statistical analysis Data were analysed in R. Categorical variables were summarized as frequencies and percentages. Because SCC data were right-skewed, they were summarized using medians and interquartile ranges (IQR), and differences across CMT score categories were assessed using the Kruskal-Wallis test 26 . Associations between quarter-level CMT positivity and categorical explanatory variables were first evaluated using chi-square tests. Variables considered epidemiologically relevant or associated in univariable analysis were entered into a multivariable generalized estimating equation (GEE) logistic regression model with a logit link and exchangeable working correlation structure, using camel identity as the clustering variable to account for correlation among quarters within the same animal 27 . Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were reported. All tests were two-sided, and p < 0.05 was considered statistically significant. Results Study population characteristics A total of 384 lactating dromedary camels were enrolled from pastoral and peri-urban production systems in Somalia, contributing 1,536 quarter milk samples for quarter-level analyses. Of these, 223 (58.1%) camels were from pastoral herds and 161 (41.9%) from peri-urban herds. Body condition score differed significantly between production systems: poor body condition (≤ 2.5) was more common in pastoral camels (44.8%) than in peri-urban camels (14.9%), whereas good body condition (≥ 3.5) was more frequent in peri-urban camels (50.9%) than in pastoral camels (22.0%) (p < 0.001). Age group and parity distributions did not differ significantly between production systems (Table 1 ). Table 1 Study population characteristics by production system (n = 384 camels). Variable Category Overall n (%) Pastoral n (%) Peri-urban n (%) p-value Age group 5 years 203 (52.9) 113 (50.7) 90 (55.9) Parity 1 calving 126 (32.8) 73 (32.7) 53 (32.9) 0.360 2–3 calvings 121 (31.5) 76 (34.1) 45 (28.0) ≥ 4 calvings 137 (35.7) 74 (33.2) 63 (39.1) Body condition score ≤ 2.5 (poor) 124 (32.3) 100 (44.8) 24 (14.9) < 0.001 3.0 (moderate) 129 (33.6) 74 (33.2) 55 (34.2) ≥ 3.5 (good) 131 (34.1) 49 (22.0) 82 (50.9) (Insert Table 1 ) Clinical, subclinical, and bacteriological mastitis outcomes At camel level, 186/384 camels (48.4%) had clinical mastitis, 352/384 (91.7%) had at least one CMT-positive quarter, and 262/384 (68.2%) had at least one culture-positive quarter. At quarter level, 254/1,536 quarters (16.5%) had clinical mastitis, 734/1,536 (47.8%) were CMT-positive, and 378/1,536 (24.6%) were culture-positive. By quarter, CMT positivity ranged from 44.8% in the right fore quarter to 50.3% in the right hind quarter, while culture positivity ranged from 22.1% in the right fore quarter to 26.8% in the left hind quarter (Table 2 ; Fig. 1 ). Table 2 Mastitis indicators at camel and quarter levels. Level Measure n Clinical mastitis n (%) CMT positive n (%) Culture positive n (%) Camel Any quarter affected 384 186 (48.4) 352 (91.7) 262 (68.2) Quarter Left fore 384 68 (17.7) 183 (47.7) 92 (24.0) Quarter Right fore 384 48 (12.5) 172 (44.8) 85 (22.1) Quarter Left hind 384 67 (17.4) 186 (48.4) 103 (26.8) Quarter Right hind 384 71 (18.5) 193 (50.3) 98 (25.5) Quarter overall All quarters 1,536 254 (16.5) 734 (47.8) 378 (24.6) Quarter-level CMT positivity was higher in peri-urban than in pastoral production systems in the stratified comparison shown in Fig. 2 (Fig. 2 ). (Insert Table 2 ) (Insert Fig. 1 ) (Insert Fig. 2 ) Bacterial isolates recovered from culture-positive milk samples Among the interpretable single-pathogen isolates presented in Table 3 , coagulase-negative staphylococci were the most frequently recovered organisms (106; 28.5%), followed by Staphylococcus aureus (82; 22.0%), Escherichia coli (49; 13.2%), Streptococcus agalactiae (41; 11.0%), Streptococcus uberis (37; 9.9%), Trueperella pyogenes (30; 8.1%), and Corynebacterium spp. (27; 7.3%). Six culture-positive samples with mixed growth were excluded from the pathogen distribution table (Table 3 ; Fig. 3 ). Table 3 Distribution of bacterial isolates from culture-positive milk samples (n = 378). Pathogen n % Coagulase-negative staphylococci 106 28.5 Staphylococcus aureus 82 22.0 Escherichia coli 49 13.2 Streptococcus agalactiae 41 11.0 Streptococcus uberis 37 9.9 Trueperella pyogenes 30 8.1 Corynebacterium spp. 27 7.3 Note: Six culture-positive samples with mixed growth were excluded from the pathogen distribution table. Percentages are based on interpretable single-pathogen isolates only. (Insert Table 3 ) (Insert Fig. 3 ) Somatic cell count according to CMT category Somatic cell count increased progressively across CMT categories. Among the 1,419 quarter milk samples with SCC measurements, the median SCC was 99,548 cells/mL (IQR: 69,212 − 142,720) for CMT score 0, 168,872 cells/mL (128,358 − 218,897) for trace, 350,753 cells/mL (270,270–464,538) for score 1, 1,077,864 cells/mL (830,662-1,364,948) for score 2, and 2,542,414 cells/mL (1,669,050 − 3,739,685) for score 3. Differences across CMT categories were statistically significant (Kruskal-Wallis, p < 0.001) (Table 4 ; Fig. 4 ). Table 4 Somatic cell count by CMT category (n = 1,419 quarters with SCC measured). CMT score n Median SCC (IQR), cells/mL 0 522 99,548 (69,212 − 142,720) Trace 218 168,872 (128,358 − 218,897) 1 295 350,753 (270,270–464,538) 2 180 1,077,864 (830,662-1,364,948) 3 204 2,542,414 (1,669,050 − 3,739,685) (Insert Table 4 ) (Insert Fig. 4 ) Factors associated with quarter-level CMT positivity In the multivariable generalized estimating equation logistic regression model, quarters from peri-urban camels had higher odds of CMT positivity than quarters from pastoral camels (AOR 1.53, 95% CI 1.24–1.89; p < 0.001). Compared with quarters without teat lesions, quarters with mild teat lesions had higher odds of CMT positivity (AOR 1.54, 95% CI 1.12–2.10; p = 0.008), as did quarters with severe teat lesions (AOR 2.02, 95% CI 1.28–3.18; p = 0.003). Moderate teat lesions were not significantly associated with CMT positivity (AOR 1.11, 95% CI 0.85–1.44; p = 0.448). Tick severity and quarter position were not significantly associated with the outcome in the adjusted model (Table 5 ; Fig. 5 ). Table 5 Multivariable generalized estimating equation logistic regression for quarter-level CMT positivity. Variable Category AOR (95% CI) p-value Production system (ref: Pastoral) Peri-urban 1.53 (1.24–1.89) < 0.001 Teat lesion severity (ref: None) Mild 1.54 (1.12–2.10) 0.008 Moderate 1.11 (0.85–1.44) 0.448 Severe 2.02 (1.28–3.18) 0.003 Tick severity (ref: None) Mild 0.89 (0.70–1.14) 0.347 Moderate 1.19 (0.91–1.56) 0.206 Severe 0.86 (0.63–1.18) 0.362 Quarter sampled (ref: LF) RF 0.89 (0.66–1.20) 0.438 LH 1.03 (0.78–1.37) 0.825 RH 1.11 (0.83–1.50) 0.484 (Insert Table 5 ) (Insert Fig. 5 ) Antibiotic residue screening Of the 384 milk samples available for residue analysis, 360 were screened using Delvotest®. Of these, 270/360 (75.0%) were negative, 56/360 (15.6%) were positive, and 34/360 (9.4%) were unclear. Sixty Delvotest® positive or unclear samples were subsequently tested using Trisensor®, of which 18/60 (30.0%) were positive and 42/60 (70.0%) were negative; six additional Trisensor® results were classified as unclear. Among Trisensor®-positive samples, beta-lactams were the most frequently detected residue group (10/18; 56%), followed by sulfonamides (4/18; 22%), tetracyclines (2/18; 11%), and beta-lactams plus tetracyclines (2/18; 11%). No sample was positive for the combined presence of beta-lactams, tetracyclines, and sulfonamides (Tables 6 and 7 ). Table 6 Number of screening tests and results of Delvotest® by production system and district. Result / test step Total Pastoral total Afgooye Walan weyn Yaaqbariweyne Peri-urban total Dharkenley Garasbaley Kaxda Samples (milk samples collected) 384 223 90 66 67 161 64 48 49 Delvotest® (tested) 360 209 84 62 63 151 61 45 45 Negative 270 170 68 50 52 100 41 30 29 Positive 56 21 9 6 6 35 14 10 11 Unclear 34 18 7 6 5 16 6 5 5 Trisensor (subset tested) 60 20 8 6 6 40 16 12 12 Spoilt/insufficient milk 24 14 6 4 4 10 3 3 4 Table 7 Screening test results by the Trisensor®. Antibiotic residue group (Trisensor®) No. of Trisensor positives % of Trisensor positive % of all Delvotest® tested* No. of unclear All Trisensor results 18 7.5 6 Beta-lactams 10 56 4.2 3 Tetracyclines 2 11 0.8 0 Sulfonamides 4 22 1.7 0 Beta-lactams + tetracyclines 2 11 0.8 2 Beta-lactams + tetracyclines + sulfonamides 0 0 0.0 1 * Estimated relative to all Delvotest®-tested samples ( n = 360), based on the subset subsequently analysed by Trisensor®. (Insert Table 6 ) (Insert Table 7 ) Discussion Burden of mastitis across production systems This study demonstrates a high burden of udder disease in lactating dromedary camels in Somalia. The quarter-level clinical mastitis prevalence (16.5%) was close to that reported from southern Ethiopia, supporting the view that clinical mastitis is a common problem across dryland camel systems in the Horn of Africa. The much higher frequency of CMT-positive than clinically affected quarters further indicates that subclinical inflammation constitutes a major hidden component of disease burden, particularly where routine screening is limited. These findings are consistent with previous camel studies showing that mastitis remains an important constraint to milk production, udder health, and milk quality under traditional and semi-commercial production conditions 9 , 11 , 12 , 15 , 28 , 29 . Comparisons across studies should, however, be made cautiously because outcome definitions, diagnostic criteria, and unit of analysis differ substantially. Bacteriological profile and epidemiological interpretation The isolate profile was dominated by coagulase-negative staphylococci and Staphylococcus aureus , with additional recovery of Escherichia coli , streptococci, Trueperella pyogenes , and Corynebacterium spp. This pattern is broadly consistent with earlier reports from camel systems in Ethiopia, Kenya, and elsewhere in which Gram-positive cocci, especially staphylococci, predominate, while environmental pathogens also contribute to infection pressure 5 , 9 , 12 , 15 , 16 , 30 . The prominence of coagulase-negative staphylococci is noteworthy because these organisms are increasingly regarded as relevant intramammary pathogens in camels rather than simple contaminants, particularly in subclinical infection 12 , 13 . Overall, the bacteriological pattern suggests that mastitis in Somali camels reflects both contagious and environmental transmission, implying that control will require combined attention to milking hygiene, teat health, and the cleanliness of the milking environment rather than reliance on a single intervention 10 – 12 . Diagnostic interpretation of CMT and somatic cell count A major internal strength of the study was the clear progressive increase in SCC across CMT categories. This stepwise gradient supports the biological usefulness of CMT as a practical indicator of mammary inflammation in Somali camels and is consistent with earlier studies reporting positive relationships among CMT reactivity, SCC, and mastitis status in dromedaries 6 , 13 , 14 , 31 . The finding also accords with broader mastitis literature showing that indirect screening tests reflect inflammatory response rather than direct bacterial recovery alone 10 , 25 . In the present study, CMT positivity was substantially more frequent than culture positivity. This is biologically plausible because CMT detects inflammatory change, whereas culture depends on recovery of viable organisms at the time of sampling. Positive CMT reactions may therefore occur in quarters with low bacterial load, intermittent shedding, prior partial resolution of infection, or non-bacterial irritation, while culture may underestimate infection because of viability loss, transport conditions, or previous antimicrobial exposure 10 , 12 , 25 . Taken together, these findings support the use of CMT, SCC, and bacteriology as complementary rather than interchangeable tools in camel mastitis surveillance. Factors associated with quarter-level CMT positivity The multivariable analysis identified peri-urban production system and teat lesion severity as the principal predictors of quarter-level CMT positivity. Both findings point to modifiable management-related risk. The association with teat lesions is biologically credible because damage to the teat skin or canal may weaken the udder’s natural defense barrier, facilitate bacterial entry, and sustain local inflammation. Similar associations have been reported in camel studies from other settings, supporting teat-health management as a practical intervention point 12 , 15 , 18 , 30 . The higher odds of CMT positivity in peri-urban herds are also important. Peri-urban camel dairying is often more market-oriented and may involve more frequent handling, closer confinement, repeated contact with containers or equipment, and greater pressure for regular milk offtake. Where hygiene and udder-health monitoring do not improve in parallel with intensification, these conditions may increase mastitis risk. This interpretation is consistent with wider evidence from camel milk systems showing that commercialization can increase both dairy opportunity and hygiene-related disease pressure 2 , 3 , 7 , 8 , 32 . By contrast, host-level variables such as age and parity were not dominant predictors in the final model, underscoring the context-specific nature of camel mastitis epidemiology across study settings and diagnostic definitions 5 , 11 , 12 , 15 . Antibiotic residues and milk-safety implications The residue-screening component identified Delvotest® positive or unclear reactions in a notable proportion of samples, and Trisensor® confirmed residues in a subset, with beta-lactams predominating. Because confirmatory testing was restricted to Delvotest® positive or unclear samples, these results should be interpreted as evidence of residue occurrence rather than as a population-level prevalence estimate. Even so, the detection of confirmed residues indicates that antimicrobial exposure and withdrawal compliance are relevant concerns in at least part of the Somali camel milk chain. This is important because camel milk is often marketed through informal channels and may be consumed raw or only minimally processed, increasing the interface between udder health, treatment practices, and consumer safety 2 , 3 , 8 , 33 . Emerging camel-specific evidence also suggests caution in extrapolating withdrawal assumptions directly from cattle, since residue persistence in camel milk may differ under some treatment conditions 19 . These findings support an integrated approach in which mastitis control, prudent antimicrobial use, and milk-quality assurance are addressed together. Strengths and limitations This study has several strengths. It included a relatively large sample of lactating camels, quarter-level assessment of all four udder quarters, and a multi-method design combining clinical examination, CMT, SCC, bacteriology, and ancillary residue screening. The use of GEE modelling strengthened inference by accounting for clustering of quarters within camels. In addition, the study provides rare comparative evidence from pastoral and peri-urban camel production systems in Somalia, where integrated mastitis epidemiology remains poorly documented 11 , 12 , 15 . Some limitations should also be recognized. The cross-sectional design limits causal inference. Culture-based diagnosis may have underestimated infection in some inflamed quarters, and the selected CMT threshold may have increased sensitivity to inflammatory change relative to bacteriological confirmation. Some explanatory variables also had incomplete field observations, and the residue analysis was descriptive and based on subset testing rather than full confirmatory screening of all samples. Nevertheless, the overall consistency of the clinical, CMT, SCC, bacteriological, and regression findings supports the conclusion that mastitis is widespread and management-relevant in Somali camel dairying. Conclusions Mastitis is widespread in lactating dromedary camels in Somalia, with subclinical infection substantially more frequent than overt clinical disease. The predominance of staphylococci, the progressive rise in SCC across CMT categories, and the higher odds of CMT positivity in peri-urban herds and quarters with teat lesions indicate that camel mastitis in this setting is both biologically important and management-sensitive. The detection of antibiotic residues in a subset of milk samples further highlights the need to integrate udder-health control with prudent antimicrobial use and milk-safety monitoring. Strengthened routine screening, improved teat and milking hygiene, and targeted herd-health interventions are likely to reduce mastitis burden and improve camel milk quality in Somali production systems. Abbreviations AOR Adjusted odds ratio AMR Antimicrobial resistance BCS Body condition score CI Confidence interval CMT California Mastitis Test CNS Coagulase-negative staphylococci DIM Days in milk GEE Generalized estimating equation IQR Interquartile range OR Odds ratio SCC Somatic cell count SD Standard deviation SE Standard error TriSensor Multi-residue screening test Declarations Ethics approval and consent to participate Ethical approval for the study was obtained from the Research Ethics Committee of the Faculty of Veterinary Medicine and Animal Husbandry, Somali National University (Approval No. SNU-FVM/2024/25). Informed permission to access herds and collect milk samples was obtained from camel owners or herders before field procedures were undertaken. All animal handling, clinical examination, and milk sampling procedures were performed by trained personnel using low-stress restraint and routine veterinary hygiene precautions. Sampling was limited to standard udder-health examination and milk collection. Owner-level information was treated confidentially and used solely for research purposes. Consent for publication Not applicable. Availability of data and materials The datasets analysed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding The authors received no specific funding for this work. Authors' contributions SAM, DHM, AAG, AJA, IAN, HMF and HMH contributed to the conception and design of the study. SAM, DHM, AAG, AJA, IAN and HMH contributed to field coordination, data acquisition and study implementation. HMF contributed technical input and academic oversight. DHM prepared the first draft of the manuscript. All authors critically revised the manuscript for important intellectual content, read and approved the final manuscript. Acknowledgements The authors gratefully acknowledge the support of Somali National University, particularly the Centre for Excellence in Camel Research & Development (CE-CaRD) and the Faculty of Veterinary Medicine and Animal Husbandry. The authors also thank the collaborating academic institutions for their support and all camel owners, herders and field participants who facilitated data collection and contributed to the successful implementation of the study. References Farah Z, Mollet M, Younan M, Dahir R. Camel dairy in Somalia: Limiting factors and development potential. Livest Sci. 2007;110(1–2):187–91. Nori M. Along the Milky Way: Marketing Camel Milk in Puntland, Somalia. Eur J Dev Res. 2010;22(5):696–714. 10.1057/ejdr.2010.40 . Oselu S, Ebere R, Arimi JM, Camels. Camel Milk, and Camel Milk Product Situation in Kenya in Relation to the World. Int J Food Sci. 2022;2022:1237423. 10.1155/2022/1237423 . Mumin DH, Mohamed SS, Abdullahi MA, Mohamed SA, Ali AA, Thomson PC. Breeding practices and trait preferences among smallholder cattle keepers in Somalia: a participatory survey. Pastoralism. 2025;15:15139. 10.3389/past.2025.15139 . Ahmad S, Yaqoob M, Bilal MQ, et al. Risk factors associated with prevalence and major bacterial causes of mastitis in dromedary camels (Camelus dromedarius) under different production systems. Trop Anim Health Prod. 2012;44(1):107–12. 10.1007/s11250-011-9895-0 . Nagy P, Thomas S, Markó O, Juhász J. Milk production, raw milk quality and fertility of dromedary camels (Camelus Dromedarius) under intensive management. Acta Vet Hung. 2013;61(1):71–84. 10.1556/AVet.2012.051 . Nagy PP, Skidmore JA, Juhasz J. Intensification of camel farming and milk production with special emphasis on animal health, welfare, and the biotechnology of reproduction. Anim Front. 2022;12(4):35–45. 10.1093/af/vfac043 . Muloi D, Alarcon P, Ombui J, et al. Value chain analysis and sanitary risks of the camel milk system supplying Nairobi city, Kenya. Prev Vet Med. 2018;159:203–10. 10.1016/j.prevetmed.2018.09.010 . Abera M, Abdi O, Abunna F, Megersa B. Udder health problems and major bacterial causes of camel mastitis in Jijiga, Eastern Ethiopia: implication for impacting food security. Trop Anim Health Prod. 2010;42(3):341–7. 10.1007/s11250-009-9424-6 . Ruegg PL. A 100-Year Review: Mastitis detection, management, and prevention. J Dairy Sci. 2017;100(12):10381–97. 10.3168/jds.2017-13023 . Seligsohn D, Nyman AK, Younan M, et al. Subclinical mastitis in pastoralist dairy camel herds in Isiolo, Kenya: Prevalence, risk factors, and antimicrobial susceptibility. J Dairy Sci. 2020;103(5):4717–31. 10.3168/jds.2019-17701 . Aqib AI, Muzammil I, Naseer MA, et al. Pathological insights into camel mastitis. Acta Trop. 2022;231:106415. 10.1016/j.actatropica.2022.106415 . Abdel Gadir Atif E, Hildebrandt G, Kleer JN, Molla B, Kyule MN, Baumann MPO. Comparison of California Mastitis Test (CMT), Somatic Cell Counts (SCC) and bacteriological examinations for detection of camel (Camelus dromedarius) mastitis in Ethiopia. Berl Munch Tierarztl Wochenschr. 2006;119(1–2):45–9. Alhafiz GA, Alghatam FH, Almohammed H, Hussen J. Milk immune cell composition in dromedary camels with subclinical mastitis. Front Veterinary Sci. 2022;9:885523. Geresu MA, Abera Leliso S, Liben GW. Camel Mastitis: Prevalence, Risk Factors, and Isolation of Major Bacterial Pathogens in Gomole District of Borena Zone, Southern Ethiopia. Ortega-Pacheco A, ed. Veterinary Medicine International . 2021;2021:1–11. 10.1155/2021/9993571 Mwangi WE, Gitau GK, Ikiror D, et al. The prevalence, antimicrobial sensitivity, and factors associated with camel mastitis in Isiolo County, Kenya. Vet World. 2022;15(12):2962–70. 10.14202/vetworld.2022.2962-2970 . Jama MM, Hussein HA, Darod ZA, Ahad AA. Determination of prevalence of subclinical mastitis, characterization of intra-mammary infection-causing bacteria, and antibiotic susceptibility in dairy camels in Jigjiga City, Somali region, Ethiopia. Front Vet Sci. 2024;11:1398118. 10.3389/fvets.2024.1398118 . Selim A, Marzok M, Gattan HS, Ismail H. Prevalence of mastitis and its associated risk factors in lactating camels in Northern Egypt. Germon P, ed. PLoS One . 2025;20(10):e0333826. 10.1371/journal.pone.0333826 Bilal Z, Amutova F, Kabdullina Z et al. Study of biological safety of camel milk after treatment with different antibiotics. Khamesipour F, ed. PLoS ONE . 2025;20(4):e0321807. 10.1371/journal.pone.0321807 Cochran W. Sampling Techniques, 3d ed Wiley. New York . Published online 1977. Schalm O, Noorlander D. Experiments and observations leading to development of the California mastitis test. Published online 1957. Gray D, Schalm O. Interpretation of the California mastitisi test results on milk from individual mammary quarters, bucket milk, and bulk herd milk. Published online 1960. Kivaria FM, Noordhuizen JPTM, Nielen M. Interpretation of California mastitis test scores using Staphylococcus aureus culture results for screening of subclinical mastitis in low yielding smallholder dairy cows in the Dar es Salaam region of Tanzania. Prev Vet Med. 2007;78(3–4):274–85. 10.1016/j.prevetmed.2006.10.011 . International Organization for Standardization. ISO 13366-2:2006. ISO. 2006. Accessed March 14, 2026. https://www.iso.org/standard/40260.html Adkins PRF, Middleton JR. Methods for Diagnosing Mastitis. Veterinary Clin North America: Food Anim Pract. 2018;34(3):479–91. 10.1016/j.cvfa.2018.07.003 . Kruskal WH, Wallis WA. Use of ranks in one-criterion variance analysis. J Am Stat Assoc. 1952;47(260):583–621. Liang KY, Zeger SL. Longitudinal data analysis using generalized linear models. biometrika . Published online 1986:13–22. Bekele T, Molla B. Mastitis in lactating camels (Camelus dromedarius) in Afar Region, north-eastern Ethiopia. Berl Munch Tierarztl Wochenschr. 2001;114(5–6):169–72. Seifu E, Tafesse B. Prevalence and etiology of mastitis in traditionally managed camels (Camelus dromedarius) in selected pastoral areas in eastern Ethiopia. Ethiop Vet J. 2011;14(2):103–14. 10.4314/evj.v14i2.63887 . Regassa A, Golicha G, Tesfaye D, Abunna F, Megersa B. Prevalence, risk factors, and major bacterial causes of camel mastitis in Borana Zone, Oromia Regional State, Ethiopia. Trop Anim Health Prod. 2013;45(7):1589–95. 10.1007/s11250-013-0403-6 . Aljumaah RS, Almutairi F, Ayadi M, Alshaikh MA, Al-Haidary AA, Samara EM. Practicability of somatic cell count and electrical conductivity as subclinical mastitis diagnostic tests in camels (Camelus dromedarius). Sci agric (Piracicaba, Braz) . 2020;77(4):e202180373. 10.1590/1678-992x-2018-0373 Noor I, Guliye A, Tariq M, Bebe B. Assessment of camel and camel milk marketing practices in an emerging peri-urban production system in Isiolo County, Kenya. Pastor Res Policy Pract. 2013;3(1):28. 10.1186/2041-7136-3-28 . Ahlberg S, Korhonen H, Lindfors E, Kang’ethe E. Analysis of antibiotic residues in milk from smallholder farms in Kenya. Afr J Dairy Farming Milk Prod. 2016;3(3):i–152. Additional Declarations No competing interests reported. Supplementary Files CamelMastitisSupplementaryTables.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 21 Apr, 2026 Editor invited by journal 28 Mar, 2026 Editor assigned by journal 26 Mar, 2026 Submission checks completed at journal 26 Mar, 2026 First submitted to journal 26 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9233776","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":615781149,"identity":"03f234fa-0f6a-41e1-9901-6261a4526904","order_by":0,"name":"Shafii Abdullahi Mohamed","email":"","orcid":"","institution":"Somali National University","correspondingAuthor":false,"prefix":"","firstName":"Shafii","middleName":"Abdullahi","lastName":"Mohamed","suffix":""},{"id":615781151,"identity":"13560c73-9614-4b96-95cd-1460ad5efb10","order_by":1,"name":"Daha Hussein Mumin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9klEQVRIiWNgGAWjYLCCBzDGBwhlQFhLAohgY2BgnEGyFmYeYrTwt59OfJDAYCdnLt/78LHNnzuJDezN2yQY/tjg1CJxJnezQQJDsrFlG7uxcW7bs8QGnmNlEoxtaTi1GDDkbpNIYDiQuOEYG5t0bsPhxAaJHDMJxobDuLXwv93+A6ilHqiF/bfFH6AW+TdmQIfh0SKRuw3o/QMJBkBbmBnYQLbwALWw4dYicePtZokEg2TDDcfSmCV72w4bt/GkFVsk4vELf3/uxg8fKuzkDQ4fY/zw489h2X72wxtvfMATYrBAQAA2EJFAQMMoGAWjYBSMAvwAANytT/VBZuUTAAAAAElFTkSuQmCC","orcid":"","institution":"Somali National University","correspondingAuthor":true,"prefix":"","firstName":"Daha","middleName":"Hussein","lastName":"Mumin","suffix":""},{"id":615781157,"identity":"fda609fc-5ca1-4819-9c23-9b2117afab87","order_by":2,"name":"Anfac Abdullahu Guled","email":"","orcid":"","institution":"Somali National University","correspondingAuthor":false,"prefix":"","firstName":"Anfac","middleName":"Abdullahu","lastName":"Guled","suffix":""},{"id":615781160,"identity":"93c31d61-8e58-4ca7-8614-96f081aebdcb","order_by":3,"name":"Abdillahi Jama Abdi","email":"","orcid":"","institution":"Somali National University","correspondingAuthor":false,"prefix":"","firstName":"Abdillahi","middleName":"Jama","lastName":"Abdi","suffix":""},{"id":615781167,"identity":"0750d33c-f5dd-4f35-97dc-47736acfcd03","order_by":4,"name":"Ibrahim Abdullahi Nur","email":"","orcid":"","institution":"Somali National University","correspondingAuthor":false,"prefix":"","firstName":"Ibrahim","middleName":"Abdullahi","lastName":"Nur","suffix":""},{"id":615781169,"identity":"79957607-ea5b-4e26-becc-bb72954f880a","order_by":5,"name":"Hussein Mohamed Farah","email":"","orcid":"","institution":"University of Naples Federico II","correspondingAuthor":false,"prefix":"","firstName":"Hussein","middleName":"Mohamed","lastName":"Farah","suffix":""},{"id":615781171,"identity":"1cd4c533-5140-4d7c-9a3e-174294561900","order_by":6,"name":"Hassan Mohamed Hassan","email":"","orcid":"","institution":"Somali National University","correspondingAuthor":false,"prefix":"","firstName":"Hassan","middleName":"Mohamed","lastName":"Hassan","suffix":""}],"badges":[],"createdAt":"2026-03-26 11:54:35","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9233776/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9233776/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105975138,"identity":"6602df70-c6e5-4523-9b6f-c0e76e3e6d11","added_by":"auto","created_at":"2026-04-02 05:06:10","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":86303,"visible":true,"origin":"","legend":"\u003cp\u003ePrevalence of mastitis indicators at camel and quarter levels in lactating dromedary camels in Somalia. The figure shows the prevalence of clinical mastitis, CMT positivity, and bacteriological culture positivity at camel level and quarter level. Camel-level prevalence was defined as the presence of at least one affected quarter per camel. Quarter-level prevalence was calculated using all examined quarters. CMT, California Mastitis Test.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9233776/v1/6b3673cc7f93b2c83bf3d86f.jpg"},{"id":105975141,"identity":"c2cac293-ae22-4b7b-b162-c1a005b0e24b","added_by":"auto","created_at":"2026-04-02 05:06:10","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":31211,"visible":true,"origin":"","legend":"\u003cp\u003eQuarter-level prevalence of CMT positivity by production system. Bars show the proportion of quarter milk samples classified as CMT-positive in pastoral and peri-urban production systems. CMT positivity was defined as a score of at least 1.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9233776/v1/f83cf9a41bb5fa01885d2eca.jpg"},{"id":106093502,"identity":"98761783-8e50-4615-aa92-e02ddacbcab6","added_by":"auto","created_at":"2026-04-03 11:37:38","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":69942,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of bacterial isolates recovered from culture-positive quarter milk samples. The figure presents the frequency distribution of major bacterial pathogens isolated from culture-positive milk samples. Percentages are based on interpretable single-pathogen isolates; samples with mixed non-interpretable growth were excluded from the pathogen distribution summary.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9233776/v1/e1e92c594b59f3ce2bde938b.jpg"},{"id":106094261,"identity":"615a1a1e-eeb3-4fa2-bc42-1d5bc243c549","added_by":"auto","created_at":"2026-04-03 11:41:59","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":64196,"visible":true,"origin":"","legend":"\u003cp\u003eSomatic cell count distribution across California Mastitis Test categories. The figure illustrates somatic cell count (SCC) values across CMT score categories (0, Trace, 1, 2, and 3) among quarter milk samples with SCC measurements. SCC increased progressively with increasing CMT score. CMT, California Mastitis Test; SCC, somatic cell count.\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9233776/v1/512dffad2620ef3151c738fe.jpg"},{"id":105975140,"identity":"770e5bc2-45c7-46f3-ac27-12d4fe7f156c","added_by":"auto","created_at":"2026-04-02 05:06:10","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":41157,"visible":true,"origin":"","legend":"\u003cp\u003eAdjusted predictors of quarter-level CMT positivity in the generalized estimating equation model. The figure shows adjusted odds ratios and 95% confidence intervals for variables retained in the multivariable GEE logistic regression model assessing quarter-level CMT positivity. The model accounted for clustering of quarters within camels. AOR, adjusted odds ratio; CI, confidence interval; CMT, California Mastitis Test; GEE, generalized estimating equation.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9233776/v1/ed9c9c91e0c0934f0981af5c.jpg"},{"id":106095800,"identity":"e5663848-697c-447d-b523-7664aa1336d6","added_by":"auto","created_at":"2026-04-03 11:51:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1603232,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9233776/v1/631a3026-4d02-41b5-aac9-82be5197b13a.pdf"},{"id":105975137,"identity":"99642c82-f508-49be-968c-d20a4ca47ca1","added_by":"auto","created_at":"2026-04-02 05:06:10","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":34151,"visible":true,"origin":"","legend":"","description":"","filename":"CamelMastitisSupplementaryTables.docx","url":"https://assets-eu.researchsquare.com/files/rs-9233776/v1/3efbbeb81f8cb9fad743ccff.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Prevalence, Bacterial Etiology, and Risk Factors of Clinical and Subclinical Mastitis in Dromedary Camels (Camelus dromedarius) Across Pastoral and Peri-Urban Production Systems in Somalia","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSomalia is one of the world\u0026rsquo;s major livestock-dependent countries, where pastoral and agro-pastoral systems operate under harsh dryland conditions and milk production remains central to food security and rural livelihoods \u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Within these systems, dromedary camels (\u003cem\u003eCamelus dromedarius\u003c/em\u003e) are especially important because they are well adapted to drought, high temperatures, erratic feed resources, and long-distance mobility, and can maintain milk production under conditions that constrain other dairy species \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. In Somalia and across the wider Horn of Africa, camel milk supports household nutrition, income generation, and livelihood resilience, while commercialization and urban demand are increasing the importance of camel dairying in both pastoral and peri-urban settings \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. However, expansion of the camel milk sector has also intensified concerns around hygienic milking, veterinary support, informal marketing, and milk safety, particularly where cold-chain infrastructure and quality assurance remain limited \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eWithin this context, udder health is a key determinant of both productivity and milk safety. Mastitis, defined as inflammation of the mammary gland, is one of the most important health constraints in dairy animals and is increasingly recognized as a major problem in camels \u003csup\u003e\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. It occurs in both clinical and subclinical forms. Clinical mastitis is characterized by visible abnormalities of the udder or milk, whereas subclinical mastitis is not readily apparent without screening and may persist while reducing milk yield, altering milk composition, and facilitating continued pathogen shedding \u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. In camel production systems, where hand-milking, calf-at-foot management, limited routine laboratory testing, and informal milk marketing are common, subclinical infection may remain undetected while still carrying biological, economic, and public-health consequences \u003csup\u003e\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eCamel mastitis is important not only because of milk loss, but also because intramammary infection affects milk quality and safety. Mastitis has been associated with elevated somatic cell counts (SCC), altered physicochemical characteristics of milk, and recovery of important bacterial pathogens \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Studies in camel dairies have shown that SCC varies with udder health status and management conditions, supporting its value as an indicator of mammary inflammation and milk-quality deterioration \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. A wide range of bacterial pathogens has been implicated, including \u003cem\u003eStaphylococcus aureus\u003c/em\u003e, coagulase-negative staphylococci, streptococci, \u003cem\u003eEscherichia coli\u003c/em\u003e, and other contagious or environmental organisms, although the relative importance of these agents varies across production systems and settings \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan additionalcitationids=\"CR16 CR17\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. This mixed contagious-environmental pattern is epidemiologically important because it implies that effective control depends on both improved milking hygiene and broader management of environmental exposure \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eMilk-safety concerns are especially relevant in camel systems because milk is often consumed raw or only minimally processed in pastoral and peri-urban settings \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Under these conditions, mastitis may increase the risk of bacterial contamination, while treatment practices can also introduce antimicrobial residues when withdrawal periods are poorly understood or not observed \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Informal camel milk value chains in East Africa have repeatedly been shown to contain hygiene gaps from production to market \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, and emerging camel-specific evidence suggests that some antibiotics may persist in milk longer than expected, underscoring the need for species-specific milk-safety data rather than simple extrapolation from cattle \u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe epidemiology of camel mastitis is shaped by interacting host, environmental, and management-related factors. Previous studies have identified associations with age, parity, stage of lactation, tick infestation, udder and teat lesions, milking hygiene, and production system \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Teat and udder lesions are particularly important because they compromise the natural barrier to infection, while production-system differences may influence stocking density, handling intensity, veterinary access, and pathogen transmission dynamics \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Diagnostic studies in dromedaries also support the use of combined screening approaches: California Mastitis Test (CMT), SCC, and bacteriological examination show positive relationships, although threshold interpretation remains partly context-specific in camels \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. In field settings where laboratory capacity may be constrained, such tools are especially relevant for routine udder-health surveillance.\u003c/p\u003e \u003cp\u003eDespite the nutritional and economic importance of camels in Somalia, integrated epidemiological evidence on camel mastitis in the country remains limited. Available studies from neighboring regions indicate that mastitis is common, multifactorial, and influenced by production environment, but Somali data remain scarce, particularly for studies that jointly assess clinical mastitis, subclinical inflammation, bacteriological positivity, and residue-related milk-safety concerns across contrasting production systems \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. This knowledge gap is important because pastoral and peri-urban camel dairying differ markedly in herd mobility, market integration, handling intensity, and management conditions, all of which may shape disease risk and milk quality \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Therefore, the present study aimed to estimate the prevalence of clinical mastitis, CMT positivity, and bacteriological culture positivity at camel and quarter levels in lactating dromedary camels in Somalia, identify associated risk factors, characterize the major bacterial isolates, and assess antibiotic residues in a subset of milk samples.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and setting\u003c/h2\u003e \u003cp\u003eThis cross-sectional study was conducted to estimate the prevalence of clinical mastitis, subclinical mastitis, and bacteriological culture positivity in lactating dromedary camels in Somalia; to identify associated risk factors; and to characterize major bacterial isolates and antibiotic residue occurrence in milk samples. The study was carried out between August 2024 and January 2026 in six districts representing two camel production systems: pastoral (Afgooye, Walanweyn, and Yaaqbariweyne) and peri-urban (Dharkenley, Garasbaley, and Kaxda).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy population and sample size\u003c/h3\u003e\n\u003cp\u003eThe study population comprised lactating one-humped camels (\u003cem\u003eCamelus dromedarius\u003c/em\u003e) managed under the selected pastoral and peri-urban production systems. Camels were eligible if they were lactating, had four accessible udder quarters, and could be safely restrained for clinical examination and milk sampling. Herds and individual camels were selected using simple random sampling within the study districts.\u003c/p\u003e \u003cp\u003eSample size was determined using Cochran\u0026rsquo;s formula for prevalence studies:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:n=\\frac{{Z}^{2}p\\left(1-p\\right)}{{d}^{2}}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere \u003cem\u003en\u003c/em\u003e is the required sample size, \u003cem\u003eZ\u003c/em\u003e is the standard normal deviate at the 95% confidence level, \u003cem\u003ep\u003c/em\u003e is the expected prevalence, and \u003cem\u003ed\u003c/em\u003e is the desired precision. Assuming an expected prevalence of 50% and a precision of 5%, the minimum required sample size was 384 camels \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. Accordingly, 384 lactating camels were enrolled, yielding 1,536 quarter-level observations.\u003c/p\u003e\n\u003ch3\u003eClinical examination and milk sampling\u003c/h3\u003e\n\u003cp\u003eField data were recorded using a structured case-record form. Camel-level variables included district, production system, age group, parity, lactation stage, body condition score, breed or ecotype, and recent antibiotic exposure when treatment history was available. Before milk collection, each camel underwent clinical examination of the udder and teats. Quarter-level observations included quarter position, teat lesion severity, and tick severity.\u003c/p\u003e \u003cp\u003eMilk samples were collected aseptically from all four udder quarters (left fore, right fore, left hind, and right hind). Teat ends were cleaned and disinfected with 70% alcohol, the first streams of milk were discarded, and approximately 10\u0026ndash;15 mL of milk was collected into sterile labelled tubes. Samples were kept chilled during handling and transport to the Somali National University Diagnostic Veterinary Laboratory for analysis.\u003c/p\u003e\n\u003ch3\u003eCalifornia Mastitis Test\u003c/h3\u003e\n\u003cp\u003eSubclinical mastitis screening was performed at the Somali National University Diagnostic Veterinary Laboratory using the California Mastitis Test (CMT), following the standard method described by \u003csup\u003e21\u003c/sup\u003e. Approximately 2 mL of milk was mixed with an equal volume of commercial CMT reagent in a paddle cup and rotated gently for 10\u0026ndash;15 s. Reactions were scored as 0, Trace, 1, 2, or 3 according to gel formation. Quarters with CMT scores of 1 or greater were classified as positive, whereas Trace was considered negative, in line with established interpretation criteria \u003csup\u003e\u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. The reagent used was WIKO\u0026reg; California Mastitis Test (Gluetec Industrial Adhesives, Germany).\u003c/p\u003e\n\u003ch3\u003eSomatic cell count\u003c/h3\u003e\n\u003cp\u003eSomatic cell count (SCC) was measured for 1,419 quarter milk samples at the Somali National University Diagnostic Veterinary Laboratory using a Fossomatic\u0026trade; 7 somatic cell counter (FOSS, Hiller\u0026oslash;d, Denmark), based on the fluoro-opto-electronic method. SCC was used as an indicator of mammary inflammation and evaluated in relation to CMT score categories \u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBacteriological analysis and isolate identification\u003c/h2\u003e \u003cp\u003eBacteriological culture and isolate identification were performed at the Somali National University Diagnostic Veterinary Laboratory. Milk aliquots were cultured on 5% sheep blood agar and MacConkey agar and incubated aerobically at 35\u0026ndash;37\u0026deg;C. Plates were examined after 18\u0026ndash;24 h and, when necessary, again at 48 h. Bacterial isolates were characterized on the basis of colony morphology, haemolysis, lactose fermentation, Gram reaction, and routine biochemical characteristics. Samples showing mixed, non-interpretable growth of unrelated colony types were classified as contaminated rather than as true intramammary infection.\u003c/p\u003e \u003cp\u003ePresumptive identification was further supported by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), with targeted molecular confirmation performed for selected isolates according to laboratory workflow.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAntibiotic residue screening\u003c/h3\u003e\n\u003cp\u003eAntibiotic residue screening was conducted at the Somali National University Diagnostic Veterinary Laboratory on a subset of milk samples. Of 384 samples available for this component, 360 were screened using Delvotest\u0026reg; (dsm-firmenich, Delft, the Netherlands) as a broad-spectrum microbial inhibitor test. Samples interpreted as positive or unclear were subsequently analysed using TriSensor\u0026reg; (Unisensor, Seraing, Belgium), a rapid dipstick assay for the detection of beta-lactams, sulfonamides, and tetracyclines in milk.\u003c/p\u003e\n\u003ch3\u003eOutcome definitions\u003c/h3\u003e\n\u003cdiv class=\"Heading\"\u003eOutcome definitions\u003c/div\u003e \u003cp\u003eThe primary outcomes were clinical mastitis, quarter-level CMT positivity, and quarter-level bacteriological culture positivity. Clinical mastitis was defined as the presence of visible abnormalities in the udder or milk detected during clinical examination. A quarter was classified as CMT-positive if the score was at least 1. A quarter was classified as culture-positive when bacterial growth was considered consistent with intramammary infection based on culture interpretation criteria. At camel level, an animal was classified as positive if at least one quarter met the relevant outcome definition.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eData were analysed in R. Categorical variables were summarized as frequencies and percentages. Because SCC data were right-skewed, they were summarized using medians and interquartile ranges (IQR), and differences across CMT score categories were assessed using the Kruskal-Wallis test \u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAssociations between quarter-level CMT positivity and categorical explanatory variables were first evaluated using chi-square tests. Variables considered epidemiologically relevant or associated in univariable analysis were entered into a multivariable generalized estimating equation (GEE) logistic regression model with a logit link and exchangeable working correlation structure, using camel identity as the clustering variable to account for correlation among quarters within the same animal \u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were reported. All tests were two-sided, and \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eStudy population characteristics\u003c/h2\u003e \u003cp\u003eA total of 384 lactating dromedary camels were enrolled from pastoral and peri-urban production systems in Somalia, contributing 1,536 quarter milk samples for quarter-level analyses. Of these, 223 (58.1%) camels were from pastoral herds and 161 (41.9%) from peri-urban herds. Body condition score differed significantly between production systems: poor body condition (\u0026le;\u0026thinsp;2.5) was more common in pastoral camels (44.8%) than in peri-urban camels (14.9%), whereas good body condition (\u0026ge;\u0026thinsp;3.5) was more frequent in peri-urban camels (50.9%) than in pastoral camels (22.0%) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Age group and parity distributions did not differ significantly between production systems (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eStudy population characteristics by production system (n\u0026thinsp;=\u0026thinsp;384 camels).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCategory\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOverall n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePastoral n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePeri-urban n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge group\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;2 years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46 (12.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e29 (13.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e17 (10.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.561\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u0026ndash;5 years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e135 (35.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e81 (36.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e54 (33.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;5 years\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e203 (52.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e113 (50.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e90 (55.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 calving\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e126 (32.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e73 (32.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e53 (32.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.360\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u0026ndash;3 calvings\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e121 (31.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e76 (34.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e45 (28.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;4 calvings\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e137 (35.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e74 (33.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e63 (39.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody condition score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;2.5 (poor)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e124 (32.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e100 (44.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e24 (14.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.0 (moderate)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e129 (33.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e74 (33.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e55 (34.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;3.5 (good)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e131 (34.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e49 (22.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e82 (50.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e(Insert Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eClinical, subclinical, and bacteriological mastitis outcomes\u003c/h2\u003e \u003cp\u003eAt camel level, 186/384 camels (48.4%) had clinical mastitis, 352/384 (91.7%) had at least one CMT-positive quarter, and 262/384 (68.2%) had at least one culture-positive quarter. At quarter level, 254/1,536 quarters (16.5%) had clinical mastitis, 734/1,536 (47.8%) were CMT-positive, and 378/1,536 (24.6%) were culture-positive. By quarter, CMT positivity ranged from 44.8% in the right fore quarter to 50.3% in the right hind quarter, while culture positivity ranged from 22.1% in the right fore quarter to 26.8% in the left hind quarter (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMastitis indicators at camel and quarter levels.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLevel\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMeasure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eClinical mastitis n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCMT positive n (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCulture positive n (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCamel\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAny quarter affected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e384\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e186 (48.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e352 (91.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e262 (68.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQuarter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLeft fore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e384\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e68 (17.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e183 (47.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e92 (24.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQuarter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRight fore\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e384\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e48 (12.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e172 (44.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e85 (22.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQuarter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLeft hind\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e384\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e67 (17.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e186 (48.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e103 (26.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQuarter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRight hind\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e384\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e71 (18.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e193 (50.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e98 (25.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQuarter overall\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll quarters\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1,536\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e254 (16.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e734 (47.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e378 (24.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eQuarter-level CMT positivity was higher in peri-urban than in pastoral production systems in the stratified comparison shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(Insert Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e(Insert Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e(Insert Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eBacterial isolates recovered from culture-positive milk samples\u003c/h2\u003e \u003cp\u003eAmong the interpretable single-pathogen isolates presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, coagulase-negative staphylococci were the most frequently recovered organisms (106; 28.5%), followed by \u003cem\u003eStaphylococcus aureus\u003c/em\u003e (82; 22.0%), \u003cem\u003eEscherichia coli\u003c/em\u003e (49; 13.2%), \u003cem\u003eStreptococcus agalactiae\u003c/em\u003e (41; 11.0%), \u003cem\u003eStreptococcus uberis\u003c/em\u003e (37; 9.9%), \u003cem\u003eTrueperella pyogenes\u003c/em\u003e (30; 8.1%), and \u003cem\u003eCorynebacterium\u003c/em\u003e spp. (27; 7.3%). Six culture-positive samples with mixed growth were excluded from the pathogen distribution table (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDistribution of bacterial isolates from culture-positive milk samples (n\u0026thinsp;=\u0026thinsp;378).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePathogen\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoagulase-negative staphylococci\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e106\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStaphylococcus aureus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEscherichia coli\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStreptococcus agalactiae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStreptococcus uberis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTrueperella pyogenes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorynebacterium spp.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eNote: Six culture-positive samples with mixed growth were excluded from the pathogen distribution table. Percentages are based on interpretable single-pathogen isolates only.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(Insert Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e(Insert Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eSomatic cell count according to CMT category\u003c/h2\u003e \u003cp\u003eSomatic cell count increased progressively across CMT categories. Among the 1,419 quarter milk samples with SCC measurements, the median SCC was 99,548 cells/mL (IQR: 69,212\u0026thinsp;\u0026minus;\u0026thinsp;142,720) for CMT score 0, 168,872 cells/mL (128,358\u0026thinsp;\u0026minus;\u0026thinsp;218,897) for trace, 350,753 cells/mL (270,270\u0026ndash;464,538) for score 1, 1,077,864 cells/mL (830,662-1,364,948) for score 2, and 2,542,414 cells/mL (1,669,050\u0026thinsp;\u0026minus;\u0026thinsp;3,739,685) for score 3. Differences across CMT categories were statistically significant (Kruskal-Wallis, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSomatic cell count by CMT category (n\u0026thinsp;=\u0026thinsp;1,419 quarters with SCC measured).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCMT score\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMedian SCC (IQR), cells/mL\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e522\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e99,548 (69,212\u0026thinsp;\u0026minus;\u0026thinsp;142,720)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTrace\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e218\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e168,872 (128,358\u0026thinsp;\u0026minus;\u0026thinsp;218,897)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e295\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e350,753 (270,270\u0026ndash;464,538)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e180\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1,077,864 (830,662-1,364,948)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e204\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2,542,414 (1,669,050\u0026thinsp;\u0026minus;\u0026thinsp;3,739,685)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(Insert Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e(Insert Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eFactors associated with quarter-level CMT positivity\u003c/h2\u003e \u003cp\u003eIn the multivariable generalized estimating equation logistic regression model, quarters from peri-urban camels had higher odds of CMT positivity than quarters from pastoral camels (AOR 1.53, 95% CI 1.24\u0026ndash;1.89; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Compared with quarters without teat lesions, quarters with mild teat lesions had higher odds of CMT positivity (AOR 1.54, 95% CI 1.12\u0026ndash;2.10; p\u0026thinsp;=\u0026thinsp;0.008), as did quarters with severe teat lesions (AOR 2.02, 95% CI 1.28\u0026ndash;3.18; p\u0026thinsp;=\u0026thinsp;0.003). Moderate teat lesions were not significantly associated with CMT positivity (AOR 1.11, 95% CI 0.85\u0026ndash;1.44; p\u0026thinsp;=\u0026thinsp;0.448). Tick severity and quarter position were not significantly associated with the outcome in the adjusted model (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultivariable generalized estimating equation logistic regression for quarter-level CMT positivity.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCategory\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAOR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProduction system (ref: Pastoral)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePeri-urban\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.53 (1.24\u0026ndash;1.89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTeat lesion severity (ref: None)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMild\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.54 (1.12\u0026ndash;2.10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.11 (0.85\u0026ndash;1.44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.448\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSevere\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.02 (1.28\u0026ndash;3.18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTick severity (ref: None)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMild\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.89 (0.70\u0026ndash;1.14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.347\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.19 (0.91\u0026ndash;1.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.206\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSevere\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.86 (0.63\u0026ndash;1.18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.362\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQuarter sampled (ref: LF)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.89 (0.66\u0026ndash;1.20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.03 (0.78\u0026ndash;1.37)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.825\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.11 (0.83\u0026ndash;1.50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.484\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(Insert Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e(Insert Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eAntibiotic residue screening\u003c/h2\u003e \u003cp\u003eOf the 384 milk samples available for residue analysis, 360 were screened using Delvotest\u0026reg;. Of these, 270/360 (75.0%) were negative, 56/360 (15.6%) were positive, and 34/360 (9.4%) were unclear. Sixty Delvotest\u0026reg; positive or unclear samples were subsequently tested using Trisensor\u0026reg;, of which 18/60 (30.0%) were positive and 42/60 (70.0%) were negative; six additional Trisensor\u0026reg; results were classified as unclear. Among Trisensor\u0026reg;-positive samples, beta-lactams were the most frequently detected residue group (10/18; 56%), followed by sulfonamides (4/18; 22%), tetracyclines (2/18; 11%), and beta-lactams plus tetracyclines (2/18; 11%). No sample was positive for the combined presence of beta-lactams, tetracyclines, and sulfonamides (Tables\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e and \u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNumber of screening tests and results of Delvotest\u0026reg; by production system and district.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eResult / test step\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePastoral total\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAfgooye\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWalan weyn\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eYaaqbariweyne\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ePeri-urban total\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eDharkenley\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eGarasbaley\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eKaxda\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSamples (milk samples collected)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e384\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e223\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e161\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDelvotest\u0026reg; (tested)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e360\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e209\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e151\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e270\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e170\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePositive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnclear\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTrisensor (subset tested)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpoilt/insufficient milk\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eScreening test results by the Trisensor\u0026reg;.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAntibiotic residue group (Trisensor\u0026reg;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo. of Trisensor positives\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e% of Trisensor positive\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e% of all Delvotest\u0026reg; tested*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNo. of unclear\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAll Trisensor results\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBeta-lactams\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTetracyclines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSulfonamides\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBeta-lactams\u0026thinsp;+\u0026thinsp;tetracyclines\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBeta-lactams\u0026thinsp;+\u0026thinsp;tetracyclines\u0026thinsp;+\u0026thinsp;sulfonamides\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cb\u003e*\u003c/b\u003e Estimated relative to all Delvotest\u0026reg;-tested samples (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;360), based on the subset subsequently analysed by Trisensor\u0026reg;.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e(Insert Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e(Insert Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e)\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eBurden of mastitis across production systems\u003c/h2\u003e \u003cp\u003eThis study demonstrates a high burden of udder disease in lactating dromedary camels in Somalia. The quarter-level clinical mastitis prevalence (16.5%) was close to that reported from southern Ethiopia, supporting the view that clinical mastitis is a common problem across dryland camel systems in the Horn of Africa. The much higher frequency of CMT-positive than clinically affected quarters further indicates that subclinical inflammation constitutes a major hidden component of disease burden, particularly where routine screening is limited. These findings are consistent with previous camel studies showing that mastitis remains an important constraint to milk production, udder health, and milk quality under traditional and semi-commercial production conditions \u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. Comparisons across studies should, however, be made cautiously because outcome definitions, diagnostic criteria, and unit of analysis differ substantially.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eBacteriological profile and epidemiological interpretation\u003c/h2\u003e \u003cp\u003eThe isolate profile was dominated by coagulase-negative staphylococci and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e, with additional recovery of \u003cem\u003eEscherichia coli\u003c/em\u003e, streptococci, \u003cem\u003eTrueperella pyogenes\u003c/em\u003e, and \u003cem\u003eCorynebacterium\u003c/em\u003e spp. This pattern is broadly consistent with earlier reports from camel systems in Ethiopia, Kenya, and elsewhere in which Gram-positive cocci, especially staphylococci, predominate, while environmental pathogens also contribute to infection pressure \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. The prominence of coagulase-negative staphylococci is noteworthy because these organisms are increasingly regarded as relevant intramammary pathogens in camels rather than simple contaminants, particularly in subclinical infection \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Overall, the bacteriological pattern suggests that mastitis in Somali camels reflects both contagious and environmental transmission, implying that control will require combined attention to milking hygiene, teat health, and the cleanliness of the milking environment rather than reliance on a single intervention \u003csup\u003e\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eDiagnostic interpretation of CMT and somatic cell count\u003c/h2\u003e \u003cp\u003eA major internal strength of the study was the clear progressive increase in SCC across CMT categories. This stepwise gradient supports the biological usefulness of CMT as a practical indicator of mammary inflammation in Somali camels and is consistent with earlier studies reporting positive relationships among CMT reactivity, SCC, and mastitis status in dromedaries \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. The finding also accords with broader mastitis literature showing that indirect screening tests reflect inflammatory response rather than direct bacterial recovery alone \u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn the present study, CMT positivity was substantially more frequent than culture positivity. This is biologically plausible because CMT detects inflammatory change, whereas culture depends on recovery of viable organisms at the time of sampling. Positive CMT reactions may therefore occur in quarters with low bacterial load, intermittent shedding, prior partial resolution of infection, or non-bacterial irritation, while culture may underestimate infection because of viability loss, transport conditions, or previous antimicrobial exposure \u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Taken together, these findings support the use of CMT, SCC, and bacteriology as complementary rather than interchangeable tools in camel mastitis surveillance.\u003c/p\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003eFactors associated with quarter-level CMT positivity\u003c/h2\u003e \u003cp\u003eThe multivariable analysis identified peri-urban production system and teat lesion severity as the principal predictors of quarter-level CMT positivity. Both findings point to modifiable management-related risk. The association with teat lesions is biologically credible because damage to the teat skin or canal may weaken the udder\u0026rsquo;s natural defense barrier, facilitate bacterial entry, and sustain local inflammation. Similar associations have been reported in camel studies from other settings, supporting teat-health management as a practical intervention point \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe higher odds of CMT positivity in peri-urban herds are also important. Peri-urban camel dairying is often more market-oriented and may involve more frequent handling, closer confinement, repeated contact with containers or equipment, and greater pressure for regular milk offtake. Where hygiene and udder-health monitoring do not improve in parallel with intensification, these conditions may increase mastitis risk. This interpretation is consistent with wider evidence from camel milk systems showing that commercialization can increase both dairy opportunity and hygiene-related disease pressure \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. By contrast, host-level variables such as age and parity were not dominant predictors in the final model, underscoring the context-specific nature of camel mastitis epidemiology across study settings and diagnostic definitions \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003eAntibiotic residues and milk-safety implications\u003c/h2\u003e \u003cp\u003eThe residue-screening component identified Delvotest\u0026reg; positive or unclear reactions in a notable proportion of samples, and Trisensor\u0026reg; confirmed residues in a subset, with beta-lactams predominating. Because confirmatory testing was restricted to Delvotest\u0026reg; positive or unclear samples, these results should be interpreted as evidence of residue occurrence rather than as a population-level prevalence estimate. Even so, the detection of confirmed residues indicates that antimicrobial exposure and withdrawal compliance are relevant concerns in at least part of the Somali camel milk chain. This is important because camel milk is often marketed through informal channels and may be consumed raw or only minimally processed, increasing the interface between udder health, treatment practices, and consumer safety \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. Emerging camel-specific evidence also suggests caution in extrapolating withdrawal assumptions directly from cattle, since residue persistence in camel milk may differ under some treatment conditions \u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. These findings support an integrated approach in which mastitis control, prudent antimicrobial use, and milk-quality assurance are addressed together.\u003c/p\u003e \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003eStrengths and limitations\u003c/h2\u003e \u003cp\u003eThis study has several strengths. It included a relatively large sample of lactating camels, quarter-level assessment of all four udder quarters, and a multi-method design combining clinical examination, CMT, SCC, bacteriology, and ancillary residue screening. The use of GEE modelling strengthened inference by accounting for clustering of quarters within camels. In addition, the study provides rare comparative evidence from pastoral and peri-urban camel production systems in Somalia, where integrated mastitis epidemiology remains poorly documented \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSome limitations should also be recognized. The cross-sectional design limits causal inference. Culture-based diagnosis may have underestimated infection in some inflamed quarters, and the selected CMT threshold may have increased sensitivity to inflammatory change relative to bacteriological confirmation. Some explanatory variables also had incomplete field observations, and the residue analysis was descriptive and based on subset testing rather than full confirmatory screening of all samples. Nevertheless, the overall consistency of the clinical, CMT, SCC, bacteriological, and regression findings supports the conclusion that mastitis is widespread and management-relevant in Somali camel dairying.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eMastitis is widespread in lactating dromedary camels in Somalia, with subclinical infection substantially more frequent than overt clinical disease. The predominance of staphylococci, the progressive rise in SCC across CMT categories, and the higher odds of CMT positivity in peri-urban herds and quarters with teat lesions indicate that camel mastitis in this setting is both biologically important and management-sensitive. The detection of antibiotic residues in a subset of milk samples further highlights the need to integrate udder-health control with prudent antimicrobial use and milk-safety monitoring. Strengthened routine screening, improved teat and milking hygiene, and targeted herd-health interventions are likely to reduce mastitis burden and improve camel milk quality in Somali production systems.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eAOR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAdjusted odds ratio\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eAMR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAntimicrobial resistance\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBCS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eBody condition score\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eConfidence interval\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCMT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCalifornia Mastitis Test\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCNS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCoagulase-negative staphylococci\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eDIM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eDays in milk\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eGEE\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGeneralized estimating equation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eIQR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eInterquartile range\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eOR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eOdds ratio\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSCC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSomatic cell count\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eStandard deviation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSE\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eStandard error\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTriSensor\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMulti-residue screening test\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eEthical approval for the study was obtained from the Research Ethics Committee of the Faculty of Veterinary Medicine and Animal Husbandry, Somali National University (Approval No. SNU-FVM/2024/25). Informed permission to access herds and collect milk samples was obtained from camel owners or herders before field procedures were undertaken. All animal handling, clinical examination, and milk sampling procedures were performed by trained personnel using low-stress restraint and routine veterinary hygiene precautions. Sampling was limited to standard udder-health examination and milk collection. Owner-level information was treated confidentially and used solely for research purposes.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eThe datasets analysed during the current study are available from the corresponding author on reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThe authors received no specific funding for this work.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eSAM, DHM, AAG, AJA, IAN, HMF and HMH contributed to the conception and design of the study. SAM, DHM, AAG, AJA, IAN and HMH contributed to field coordination, data acquisition and study implementation. HMF contributed technical input and academic oversight. DHM prepared the first draft of the manuscript. All authors critically revised the manuscript for important intellectual content, read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eThe authors gratefully acknowledge the support of Somali National University, particularly the Centre for Excellence in Camel Research \u0026amp; Development (CE-CaRD) and the Faculty of Veterinary Medicine and Animal Husbandry. The authors also thank the collaborating academic institutions for their support and all camel owners, herders and field participants who facilitated data collection and contributed to the successful implementation of the study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFarah Z, Mollet M, Younan M, Dahir R. Camel dairy in Somalia: Limiting factors and development potential. 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Afr J Dairy Farming Milk Prod. 2016;3(3):i\u0026ndash;152.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"camel mastitis, Camelus dromedarius, pastoral systems, peri-urban dairy, somatic cell count, bacterial pathogens, Somalia","lastPublishedDoi":"10.21203/rs.3.rs-9233776/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9233776/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMastitis is a major constraint to camel milk productivity, udder health, and milk safety in Somali pastoral and emerging peri-urban dairy systems, yet comparative epidemiological data across these systems remain scarce. This cross-sectional study investigated the prevalence, bacterial etiology, and risk factors of mastitis in lactating dromedary camels in Somalia, and examined the relationship between California Mastitis Test (CMT) score and somatic cell count (SCC), together with antibiotic residues in a subset of milk samples. Between August 2024 and January 2026, 384 lactating camels from pastoral and peri-urban production systems were enrolled, yielding 1,536 quarter milk samples. Clinical mastitis was assessed by udder examination, subclinical mastitis by CMT, SCC was measured in 1,419 quarter samples, and bacteriological culture was performed on quarter milk samples. At camel level, 48.4% had clinical mastitis, 91.7% had at least one CMT-positive quarter, and 68.2% had at least one culture-positive quarter. At quarter level, the prevalence of clinical mastitis, CMT positivity, and culture positivity was 16.5%, 47.8%, and 24.6%, respectively. Coagulase-negative staphylococci were the most frequent isolates (28.0%), followed by \u003cem\u003eStaphylococcus aureus\u003c/em\u003e (21.7%), \u003cem\u003eEscherichia coli\u003c/em\u003e (13.0%), \u003cem\u003eStreptococcus agalactiae\u003c/em\u003e (10.8%), and \u003cem\u003eStreptococcus uberis\u003c/em\u003e (9.8%). Median SCC increased progressively from 99,548 cells/mL in CMT score 0 quarters to 2,542,414 cells/mL in CMT score 3 quarters (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In multivariable generalized estimating equation analysis, peri-urban production system (AOR 1.54, 95% CI 1.23\u0026ndash;1.93), mild teat lesions (AOR 1.61, 95% CI 1.18\u0026ndash;2.19), and severe teat lesions (AOR 2.04, 95% CI 1.29\u0026ndash;3.24) were significantly associated with quarter-level CMT positivity. Antibiotic residue screening identified confirmed positives in a subset of milk samples, with beta-lactams predominating. These findings show that mastitis is widespread in Somali camel dairying and is shaped by both bacterial infection and modifiable management-related factors, particularly under peri-urban conditions. Improved udder-health surveillance, teat-health management, and prudent antimicrobial-use practices are needed to reduce disease burden and improve camel milk safety.\u003c/p\u003e","manuscriptTitle":"Prevalence, Bacterial Etiology, and Risk Factors of Clinical and Subclinical Mastitis in Dromedary Camels (Camelus dromedarius) Across Pastoral and Peri-Urban Production Systems in Somalia","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-02 05:06:02","doi":"10.21203/rs.3.rs-9233776/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2026-04-21T19:31:10+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-28T14:30:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-26T12:51:44+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-26T12:51:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Veterinary Research","date":"2026-03-26T11:47:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"56cdbab3-3d40-477d-b51b-1c5768b501b0","owner":[],"postedDate":"April 2nd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-21T19:38:17+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-02 05:06:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9233776","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9233776","identity":"rs-9233776","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}