Survey on the Prevalence of Buruli Ulcer among Patients with Persistent Wounds in Imo State, Nigeria

Survey on the Prevalence of Buruli Ulcer among Patients with Persistent Wounds in Imo State, Nigeria | 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 Survey on the Prevalence of Buruli Ulcer among Patients with Persistent Wounds in Imo State, Nigeria Onwuka Chigozie Divine¹, uche maduaku chukwuocha This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7470652/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Buruli ulcer (BU), caused by Mycobacterium ulcerans , is a neglected tropical disease presenting with chronic necrotizing skin lesions. In Nigeria, its role in the burden of persistent wounds is poorly understood due to diagnostic challenges and overlapping clinical presentations. Methods We conducted a multisite cross-sectional study among patients with wounds persisting ≥ 4 weeks across healthcare facilities in Imo State, Nigeria. Socio-demographic, clinical, and exposure data were collected using standardized questionnaires. Wound specimens were tested with IS2404 real-time PCR (reference standard), smear microscopy, and histopathology (subset). Logistic regression identified independent predictors of BU. Results Of 300 participants, 75 (25.0%) had PCR-confirmed BU. Most were adults aged 30–59 years (53.4%), farmers (40.0%), and individuals reporting freshwater exposure (70.0%). Lesions were mainly on the lower limbs (53.3%), large (≥ 5 cm, 66.7%), and chronic (≥ 12 weeks, 60.0%). Seventy percent initially sought care outside the formal health system. Predictors of BU included freshwater contact (aOR = 3.25, 95% CI: 1.45–7.28), lower limb lesions (aOR = 2.80, 95% CI: 1.20–6.55), and symptom duration > 12 weeks (aOR = 4.10, 95% CI: 1.85–9.08). Smear microscopy showed low sensitivity (48%) but high specificity (90%); histopathology demonstrated sensitivity of 65% and specificity of 95%. PCR achieved 100% accuracy with a median turnaround of 3 days. Conclusions BU is a substantial but under-recognized cause of persistent wounds in southeastern Nigeria. Early recognition, risk-based screening, and deployment of rapid molecular tests at peripheral facilities are essential to improving detection and outcomes. Buruli ulcer Mycobacterium ulcerans persistent wounds Nigeria PCR neglected tropical diseases Figures Figure 1 Figure 2 Introduction Buruli ulcer (BU), caused by Mycobacterium ulcerans , is a neglected tropical disease (NTD) characterized by chronic necrotizing infections of the skin and soft tissue. If left untreated, it can result in severe morbidity, permanent disability, and social stigma [ 1 , 2 ]. The disease disproportionately affects impoverished rural populations in West and Central Africa, with additional endemic foci reported in Australia and other regions [ 3 , 4 ]. Despite its devastating clinical consequences, BU remains among the most under-recognized and under-researched NTDs, ranking behind tuberculosis and leprosy in terms of global attention and funding [ 5 ]. Transmission dynamics are not fully understood, but exposure to contaminated water sources and aquatic ecosystems is strongly implicated [ 6 ]. Clinically, BU typically begins as a painless nodule, plaque, or localized edema, which progresses to ulceration with undermined edges and necrotic tissue [ 7 ]. If untreated, complications such as contractures, functional impairment, and disfigurement may occur, profoundly affecting quality of life [ 8 ]. Early detection and treatment with rifampicin–clarithromycin are highly effective and prevent long-term sequelae [ 9 ]. However, delays in diagnosis remain common due to limited community and health worker awareness, weak surveillance systems, and overlap with other chronic wounds such as diabetic, venous, or traumatic ulcers [ 10 ]. In Nigeria, BU was first reported several decades ago, yet prevalence data remain sparse, fragmented, and geographically inconsistent [ 11 , 12 ]. The disease is considered endemic in several states, particularly in the southeastern and southern regions, but systematic surveillance is limited and underreporting persists [ 13 ]. Persistent wounds are frequent presentations in healthcare and community settings; however, their underlying causes are often inadequately investigated, leading to potential misdiagnosis and missed BU cases. Evidence from West African countries highlights the value of targeted surveys among patients with chronic or non-healing wounds as a cost-effective strategy for case detection and program planning [ 14 ]. Imo State, located in southeastern Nigeria, has ecological features favorable for BU transmission, including slow-moving rivers, swamps, and rural farming practices. Despite these risk factors, the burden of BU among patients with persistent wounds remains poorly documented. This knowledge gap limits the integration of BU management into broader wound care, skin NTD control strategies, and national elimination efforts. This study therefore aimed to determine the prevalence of BU among patients with persistent wounds in Imo State, Nigeria. By generating context-specific evidence, it seeks to strengthen local surveillance, enhance case detection, and contribute to global BU elimination and integrated chronic wound management. Methods 2.1. Study setting This study was conducted in Imo State, South-Eastern Nigeria, across public and private facilities including tertiary hospitals, secondary hospitals, and high-volume primary care/wound clinics. Facilities were selected from the three senatorial zones to capture ecological variation (rural/urban and riverine/non-riverine communities). 2.2. Study design and participants We used a cross-sectional study design. Eligible participants were patients aged 15 years and older presenting with wounds persisting for at least 4 weeks despite self-care or clinical care. Patients were excluded if they were receiving active anti-mycobacterial therapy at presentation (e.g., rifampicin for tuberculosis) or if the wound was clearly attributable to malignancy or acute trauma without chronicity. This study is a cross-sectional survey (not a clinical trial). 2.3. Data collection A standardized questionnaire was administered by trained research assistants using REDCap/ODK tools. Data were collected using a structured questionnaire specifically developed for this study, adapted from WHO Buruli ulcer case-reporting tools and modified to include locally relevant socio-demographic, environmental, and health-seeking variables. The English version of the questionnaire is provided as Supplementary File 1.” 2.4. Sample size determination Sample size was estimated assuming a prevalence of Buruli ulcer (BU) of 3% among patients with persistent wounds, with a margin of error of 1.5% and 95% confidence level. The minimum sample size required was 267 participants. Allowing for 10% unusable samples and clustering by facility (design effect ~ 1.2–1.5), the final target sample size was approximately 300 participants. 2.5. Sampling and recruitment Health facilities were purposively selected to ensure representation across the three senatorial zones, levels of care (tertiary, secondary, and primary), and ecological settings (rural/urban, riverine/non-riverine). Within these facilities, all patients presenting with wounds ≥ 4 weeks were screened during routine clinic days over six months. Eligible patients were consecutively enrolled until targets were met. Screening logs recorded the number assessed, enrolled, and excluded (with reasons) to minimize selection bias. 2.6. Laboratory analysis Specimens were collected according to WHO guidelines. Two swabs were obtained from the undermined edges of ulcerative lesions or fine-needle aspirates for non-ulcerative lesions, and punch biopsies were taken when indicated. Primary testing : IS2404 real-time PCR was performed at the National Institute of Medical Research, Lagos. Supportive tests : Ziehl–Neelsen microscopy, histopathology, and culture were used where feasible. Laboratory personnel were blinded to clinical suspicion. 2.7. Case definitions Confirmed BU : IS2404 PCR positive from a compatible lesion. Probable BU : Compatible lesion with positive microscopy or typical histopathology where PCR was not available. Non-BU wound : PCR negative without other evidence of BU. 2.8. Statistical analysis Data were analyzed using Stata/R. Categorical variables were summarized as frequencies and percentages, and continuous variables as means with standard deviation or medians with interquartile range. The prevalence of PCR-confirmed BU was estimated with 95% confidence intervals. Univariable and multivariable logistic regression models were fitted to identify predictors of BU. Predictor variables included age, sex, senatorial zone, freshwater exposure, occupation, lesion site, and symptom duration. Robust standard errors were clustered by facility. Sensitivity analyses included exclusion of indeterminate PCR results, use of a composite outcome (“probable + confirmed” BU), and multiple imputation for missing data when > 5%. 2.8. Quality assurance All research staff underwent standardized training. Specimen labeling and data entry were double-checked, and 10% of specimens were retested for quality control. External quality assurance was conducted through the National Institute of Medical Research. 2.9. Ethical considerations Ethical approval was obtained from the Imo State Ministry of Health Ethics Committee. Written informed consent was obtained from all participants after study objectives, procedures, risks, and benefits were explained in a language they understood. For participants under 18 years, assent was obtained alongside informed consent from parents or guardians. This study adhered to the principles of the Declaration of Helsinki and WHO recommendations.” All confirmed cases were referred for guideline-recommended therapy (rifampicin and clarithromycin for 8 weeks). Confidentiality was maintained in line with the Declaration of Helsinki and WHO recommendations. Results 3.1 Demographic and Clinical Characteristics Among 300 participants, most were adults aged 30–59 years (51.7%) and female (53.3%). Farmers formed the largest occupational group (40.0%) and were more likely to report freshwater exposure ( p = 0.01). Diabetes was the most common comorbidity (55.0%), especially among those ≥50 years (OR = 1.86, 95% CI: 1.10–3.14). Lesions were mainly on the lower limbs (50.0%), large (≥5 cm, 66.7%), and chronic (≥12 weeks, 60.0%). Delayed presentation was strongly associated with initial care outside formal health facilities (72.4% vs. 41.3%; p < 0.001). Overall, 70.0% reported freshwater contact, significantly linked to both farming and rural residence (Table 1). 3.2. Distribution of PCR-confirmed Buruli ulcer (BU) cases Figure 1 shows that BU was most common among adults aged 30–59 years, with fewest cases in children <15 years. Females were slightly more affected than males. Lesions occurred mainly on the lower limbs, followed by the upper limbs, trunk, and head/neck region. 3.3. Prevalence of BU among patients with persistent wounds Figure 2 illustrates the prevalence of BU among 300 patients with persistent wounds. One-quarter (25%, n = 75) were PCR-confirmed as BU, while the remaining 75% (n = 225) had non-BU causes, including diabetes, trauma, vascular disease, or other infections. 3.4. Factors associated with BU positivity BU positivity was significantly associated with freshwater contact (aOR = 3.25, 95% CI: 1.45–7.28), lower limb lesions (aOR = 2.80, 95% CI: 1.20–6.55), and symptom duration >12 weeks (aOR = 4.10, 95% CI: 1.85–9.08). These findings underscore ecological exposure, lesion site, and delayed diagnosis as key predictors of BU in endemic settings (Table 2). 3.3 Logistic regression for predictors of PCR-confirmed Buruli ulcer Logistic regression analysis identified freshwater contact, lower limb lesions, and symptom duration greater than 12 weeks as independent predictors of PCR-confirmed Buruli ulcer. In contrast, demographic factors (age and sex) and comorbidities (diabetes and HIV) were not significantly associated with BU positivity. These findings underscore the role of ecological exposure, anatomical site of infection, and delayed presentation as key drivers of BU risk in endemic communities. 3.4 Diagnostic performance of tests for Buruli ulcer against the PCR reference standard Smear microscopy showed moderate sensitivity (48%) and high specificity (90%), with results available within 1 day. Histopathology (n = 60) demonstrated higher sensitivity (65%) and specificity (95%), but a longer turnaround time (median 5 days). PCR achieved 100% sensitivity and specificity, with a median turnaround of 3 days (Table 4). Discussion This study provides the first systematic assessment of BU prevalence among patients with chronic wounds in Imo State, Nigeria, and identifies key predictors of PCR-confirmed disease. We found that one in four patients with persistent wounds had BU, confirming its role as an under-recognized cause of morbidity in the region. The predominance of adult cases, particularly in the 30–59-year age group, contrasts with the traditional view of BU as primarily a childhood disease and suggests that occupational and environmental exposures—especially farming and freshwater contact—may increase adult vulnerability [ 15 , 16 ]. The clinical characteristics observed—large, chronic wounds predominantly affecting the lower limbs—are consistent with reports from West Africa, where delayed health-seeking behavior and barriers to biomedical care exacerbate morbidity [ 17 – 19 ]. The finding that 70% of patients initially sought care outside the formal health system highlights persistent gaps in awareness, trust, and access to healthcare. Similar patterns documented in Ghana and Cameroon indicate that reliance on traditional medicine contributes to diagnostic delays and poorer outcomes [ 20 , 21 ]. Regression analysis identified three independent predictors of BU positivity: freshwater exposure, lower limb involvement, and wound duration longer than 12 weeks. The strong association with freshwater supports ecological evidence implicating aquatic environments as reservoirs of M. ulcerans [ 22 , 23 ]. Lower-limb predominance likely reflects exposure during farming and household activities around rivers and swamps [ 24 ]. Delayed presentation emerged as the strongest predictor, emphasizing diagnostic delay as a major driver of disease progression. These findings align with World Health Organization reports identifying early detection as the cornerstone of effective BU control [ 25 ]. In contrast, host-related factors such as age, sex, diabetes, and HIV were not significantly associated with BU in this cohort. This suggests that environmental exposure and health-seeking behavior may play greater roles than biological susceptibility in determining infection risk [ 26 ]. Nonetheless, the high prevalence of comorbidities such as diabetes underscores the importance of integrated wound-care strategies, as these conditions can complicate management and delay healing even in non-BU cases [ 27 ]. Our diagnostic evaluation confirmed PCR as the gold standard, with high sensitivity and specificity, but its limited availability and turnaround time (median 3 days) pose challenges in resource-constrained settings [ 28 ]. Smear microscopy, though rapid and widely available, showed low sensitivity and risks underdiagnosis if used alone [ 29 ]. Histopathology offered higher accuracy but was constrained by accessibility and longer turnaround times [ 30 ]. These findings underscore the need for simplified, point-of-care molecular diagnostics that combine accuracy with speed to enable timely treatment initiation [ 31 ]. Overall, our findings highlight BU as an important but neglected cause of chronic wounds in southeastern Nigeria. Preventive strategies should prioritize reducing unsafe freshwater exposure and promoting protective practices during farming and water-related activities. At the same time, strengthening community awareness, discouraging exclusive reliance on traditional healers, and expanding access to early diagnostic services are critical for reducing disease burden. Integrating BU screening into broader chronic wound-care programs, particularly for patients presenting with persistent lower-limb lesions, could provide an effective pathway for early detection and intervention [ 19 , 31 ]. Conclusion Buruli ulcer contributed significantly to the burden of chronic wounds in this study, with freshwater exposure, lower-limb involvement, and delayed presentation identified as key predictors. While PCR remains the gold standard for diagnosis, its limited availability and the low sensitivity of smear microscopy emphasize the urgent need for rapid and reliable point-of-care tests. Enhancing community awareness, encouraging early health-seeking behavior, and integrating improved diagnostic tools into routine wound care are critical to reducing BU-related morbidity and disability. Public Health Implications The high prevalence of Buruli ulcer among patients with chronic wounds underscores the urgency of strengthening surveillance and case-finding in endemic regions of Nigeria. Given that freshwater exposure and delayed presentation are strong predictors, targeted community education should focus on farmers, fishermen, and school-aged children who are most at risk. At the health system level, integrating rapid and accurate diagnostic tools into peripheral facilities would enable timely confirmation and treatment, reducing long-term disability. Policy responses should also prioritize environmental risk reduction, capacity-building for community health workers, and resource allocation for early detection programs. Coordinated action between government, non-governmental organizations, and community stakeholders is essential to interrupt the cycle of delayed care and improve outcomes for affected populations. Strengths and Limitations This study was among the few systematic investigations of Buruli ulcer in southeastern Nigeria, focusing on persistent wounds and using PCR confirmation alongside multivariable regression to identify independent predictors for risk-based screening. However, its hospital-based design may not reflect the wider community burden, histopathology was limited to a subset, recall bias in reported exposures is possible, and the cross-sectional design restricts causal inference. Nevertheless, the findings offer robust evidence to strengthen early detection, diagnosis, and control of Buruli ulcer in endemic areas. Recommendations Our findings support the integration of BU surveillance into existing neglected tropical disease (NTD) programs. Expanding access to molecular and rapid diagnostic tools at peripheral facilities, alongside sustained training of health workers, is essential for timely case detection. Community-level interventions should also address behavioral and environmental risk factors, particularly freshwater exposure, while promoting early care-seeking. These combined approaches are necessary to reduce transmission, prevent disability, and improve patient outcomes in endemic regions. Abbreviations BU : Buruli ulcer PCR : Polymerase chain reaction NTDs : Neglected tropical diseases WHO : World Health Organization CI: Confidence interval aOR : Adjusted odds ratio EQA : External quality assurance Declarations Ethics approval and consent to participate Ethical approval was obtained from the Imo State Ministry of Health Ethics Committee. Written informed consent was obtained from all participants. For minors, parental/guardian consent and child assent were obtained. Clinical Trial Clinical trial number: Not applicable. Consent for publication Not applicable. Availability of data and material The datasets generated and/or analyzed 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 No specific funding was received for this work. Authors’ contributions OCD: Conceptualization, Methodology, Writing – Original Draft. CUM: Investigation, Data Curation, Laboratory Supervision. Both authors: Formal Analysis, Writing – Review & Editing. All authors read and approved the final manuscript. Acknowledgements We thank participating patients and families; clinical and laboratory teams at Federal Medical Center, Umuagwo Specialist Hospital, and Ejemekwuru Health Center; Imo State Ministry of Health; and community health volunteers. We acknowledge National Institute of Medical Research, Lagos, for EQA support References World Health Organization. Buruli ulcer (Mycobacterium ulcerans infection). Geneva: WHO. 2023. Available from: https://www.who.int/news-room/fact-sheets/detail/buruli-ulcer-(mycobacterium-ulcerans-infection) Yotsu RR. Buruli ulcer: clinical and epidemiological aspects. Trop Med Health. 2018;46:11. Merritt RW, Walker ED, Small PLC, Wallace JR, Johnson PDR, Benbow ME, et al. Ecology and transmission of Mycobacterium ulcerans . Emerg Infect Dis. 2010;16(3):355–63. Tai A, Athan E, Friedman ND, Hughes AJ. Buruli ulcer: an Australian perspective. Med J Aust. 2008;188(5):273–6. Simpson H, Deribe K, Tabah EN, Peters A, Molyneux D. Mapping the global distribution of Buruli ulcer: a systematic review with evidence consensus. Lancet Glob Health. 2019;7(7):e912–22. Marsollier L, Aubry J, Coutanceau E, André JP, Small PLC, Milon G, et al. Colonization of the salivary glands of Naucoris cimicoides by Mycobacterium ulcerans requires host plasmatocytes and is a model for transmission by insect bite. Infect Immun. 2005;73(9):5762–71. Junghanss T, Johnson RC, Pluschke G. Mycobacterium ulcerans disease. In: Farrar J, Hotez PJ, Junghanss T, Kang G, Lalloo D, White NJ, editors. Manson’s Tropical Diseases. 23rd ed. Elsevier; 2014. pp. 519–31. Vincent QB, Ardant MF, Marsollier L, Chauty A, Alcais A, Franco E, et al. Clinical epidemiology of laboratory-confirmed Buruli ulcer in Benin: a cohort study. Lancet Glob Health. 2014;2(7):e422–30. Nienhuis WA, Stienstra Y, Thompson WA, Awuah PC, Abass KM, Tuah W, et al. Antimicrobial treatment for early, limited Mycobacterium ulcerans infection: a randomized controlled trial. Lancet. 2010;375(9715):664–72. Wadagni AC, Barogui YT, Johnson RC, Sopoh GE, Affolabi D, Gbovi J, et al. Delays in seeking care for Buruli ulcer in Benin. PLoS Negl Trop Dis. 2019;13(5):e0007256. Oluwasanmi JO, Solankee TF, Olurin EO, Itayemi SO, Alabi GO, Lucas AO. Mycobacterium ulcerans (Buruli) skin ulceration in Nigeria. Am J Trop Med Hyg. 1976;25(1):122–8. Ukwaja KN, Meka AO, Chukwu JN, Kayode PO, Ekeke N et al. Huis In’t Veld D,. Buruli ulcer in Nigeria: a pilot case study. Trans R Soc Trop Med Hyg. 2016;110(7):460–7. Chukwu JN, Meka AO, Nwafor CC, Oshi DC, Madichie NO, Ekeke N, et al. Buruli ulcer in Nigeria: results of a pilot case study in three rural districts. Infect Dis Poverty. 2017;6(1):12. Sopoh GE, Dossou AD, Johnson RC, Barogui YT, Makoutode M, Anagonou SY, et al. Buruli ulcer surveillance, Benin, 2003–2005. Emerg Infect Dis. 2010;16(7):1204–5. Debacker M, Aguiar J, Steunou C, Zinsou C, Meyers WM, Guédénon A, et al. Mycobacterium ulcerans disease: role of age and gender in incidence and morbidity. Trop Med Int Health. 2004;9(12):1297–304. Röltgen K, Pluschke G. Epidemiology and disease burden of Buruli ulcer: a review. Res Rep Trop Med. 2015;6:59–73. Ackumey MM, Gyapong M, Pappoe M, Maclean CK, Weiss MG. Illness meanings and experiences for pre-ulcer and ulcer conditions of Buruli ulcer in the Ga-West and Ga-South municipalities of Ghana. BMC Public Health. 2012;12:264. Ahorlu CK, Koka E, Yeboah-Manu D, Lamptey I, Ampadu EO. Enhancing Buruli ulcer control in Ghana through social interventions: a case study from the Obom sub-district. BMC Public Health. 2013;13:59. Stienstra Y, van der Graaf WT, Asamoa K, van der Werf TS. Beliefs and attitudes toward Buruli ulcer in Ghana. Am J Trop Med Hyg. 2002;67(2):207–13. Mulder AA, Boerma RP, Barogui YT, Zinsou C, Johnson RC, Gbovi J, et al. Healthcare seeking behaviour for Buruli ulcer in Benin: a model to capture therapy choice of patients and healthy community members. Trans R Soc Trop Med Hyg. 2008;102(9):912–20. Alferink M, Sopoh GE, Agossadou C, Barogui YT, Zinsou C, Johnson RC, et al. Healthcare seeking behaviour and diagnostic delays for Buruli ulcer in Benin: a cross-sectional study. BMC Public Health. 2013;13:501. Williamson HR, Benbow ME, Nguyen KD, Beachboard DC, Kimbirauskas RK, McIntosh MD, et al. Distribution of Mycobacterium ulcerans in Buruli ulcer endemic and non-endemic aquatic sites in Ghana. PLoS Negl Trop Dis. 2008;2(3):e205. Marion E, Chauty A, Yeramian E, Babonneau J, Kempf M, Marsollier L. A case of guilt by association: Mycobacterium ulcerans toxin mycolactone impairs wound healing through cytotoxicity and immune modulation. PLoS Pathog. 2016;12(7):e1005473. Converse PJ, Almeida DV, Nuermberger EL, Grosset JH. Mycobacterium ulcerans infection in the mouse: dose–response studies with rifampin, streptomycin, amikacin, and clarithromycin. Antimicrob Agents Chemother. 2011;55(1):310–4. World Health Organization. Treatment of Mycobacterium ulcerans disease (Buruli ulcer): guidance for health workers. Geneva: WHO; 2012. Raghunathan PL, Whitney EA, Asamoa K, Stienstra Y, Taylor TH Jr, Amofah GK, et al. Risk factors for Buruli ulcer disease (Mycobacterium ulcerans infection): results from a case–control study in Ghana. Clin Infect Dis. 2005;40(10):1445–53. Eddyani M, Sopoh GE, Brun LV, Kestens L, Rogge D, Barogui Y, et al. Buruli ulcer and co-infection with HIV. Emerg Infect Dis. 2014;20(11):1969–76. Fyfe JA, Lavender CJ, Johnson PD, Globan M, Sievers A, Azuolas J, et al. Development and application of two multiplex real-time PCR assays for detection of Mycobacterium ulcerans in clinical and environmental samples. Appl Environ Microbiol. 2007;73(15):4733–40. Phillips R, Horsfield C, Kuijper S, Lartey A, Tetteh I, Etuaful S, et al. Sensitivity of PCR targeting IS2404 for diagnosis of Buruli ulcer. J Clin Microbiol. 2005;43(9):3650–6. Portaels F, Meyers WM, Ablordey A, Castro AG, Chemlal K, de Rijk P, et al. First cultivation and characterization of Mycobacterium ulcerans from the environment. Lancet. 1999;353(9157):986–7. Mitjà O, Marks M, Bertran L, Kollie K, Argaw D, Fahal AH, et al. Integrated control and management of skin neglected tropical diseases in sub-Saharan Africa: addressing an emerging public-health and research priority. PLoS Negl Trop Dis. 2017;11(1):e0005136. Tables Table 1 to 4 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files QuestionnaireBuruliUlcerBMC.docx Table14.docx Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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16:38:01","extension":"png","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":22227,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/b6ea2aac9d2607e5e9cfa826.png"},{"id":93065897,"identity":"3c6e12af-16ac-46fa-bd24-39b54128b70c","added_by":"auto","created_at":"2025-10-08 16:46:05","extension":"xml","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":80016,"visible":true,"origin":"","legend":"","description":"","filename":"f6690965dd444b7a80f9a2f1fed943b11structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/f611fc59f08ef97999f46be3.xml"},{"id":93062878,"identity":"ca3ed8bc-1938-462c-acec-e649a3a552a0","added_by":"auto","created_at":"2025-10-08 16:38:04","extension":"html","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":90274,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/24a283adecd748531d16ec3e.html"},{"id":93065898,"identity":"bb2d5ba7-1cab-4893-aa55-228c4866155f","added_by":"auto","created_at":"2025-10-08 16:46:05","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":109248,"visible":true,"origin":"","legend":"\u003cp\u003eBar chart showing higher prevalence in adults aged 30–59, with no major sex differences, and Lesion site distribution among PCR-confirmed Buruli ulcer cases\u003cem\u003e showing 53% lower limb, 23% upper limb, 13% trunk, 10% head/neck.)\u003c/em\u003e\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/5d68ea5684a16bb0b35c2b27.png"},{"id":93063031,"identity":"d62ff279-6898-4222-8575-1c16a8e6a3fb","added_by":"auto","created_at":"2025-10-08 16:38:06","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":79962,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution on the prevalence of Buruli ulcer among persistent wounds patients\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/cd8052667ff68accb8cf0bde.png"},{"id":100441292,"identity":"715b98ab-1889-4c91-8ebd-8777deccb51f","added_by":"auto","created_at":"2026-01-16 16:38:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":940793,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/b1035c98-83f8-4c5e-87f3-9d0eefc7cce7.pdf"},{"id":93062748,"identity":"46aa3565-0033-4ad6-a0db-aaab3087529a","added_by":"auto","created_at":"2025-10-08 16:38:03","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":47859,"visible":true,"origin":"","legend":"","description":"","filename":"QuestionnaireBuruliUlcerBMC.docx","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/a09ba4a27d5770c62bcef496.docx"},{"id":93063347,"identity":"0fd3c529-fcef-419f-9232-dbb2faad59f8","added_by":"auto","created_at":"2025-10-08 16:38:13","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":17486,"visible":true,"origin":"","legend":"","description":"","filename":"Table14.docx","url":"https://assets-eu.researchsquare.com/files/rs-7470652/v1/41962a50bfc5b633f0961c34.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Survey on the Prevalence of Buruli Ulcer among Patients with Persistent Wounds in Imo State, Nigeria","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBuruli ulcer (BU), caused by \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e, is a neglected tropical disease (NTD) characterized by chronic necrotizing infections of the skin and soft tissue. If left untreated, it can result in severe morbidity, permanent disability, and social stigma [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The disease disproportionately affects impoverished rural populations in West and Central Africa, with additional endemic foci reported in Australia and other regions [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Despite its devastating clinical consequences, BU remains among the most under-recognized and under-researched NTDs, ranking behind tuberculosis and leprosy in terms of global attention and funding [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eTransmission dynamics are not fully understood, but exposure to contaminated water sources and aquatic ecosystems is strongly implicated [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Clinically, BU typically begins as a painless nodule, plaque, or localized edema, which progresses to ulceration with undermined edges and necrotic tissue [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. If untreated, complications such as contractures, functional impairment, and disfigurement may occur, profoundly affecting quality of life [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Early detection and treatment with rifampicin\u0026ndash;clarithromycin are highly effective and prevent long-term sequelae [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. However, delays in diagnosis remain common due to limited community and health worker awareness, weak surveillance systems, and overlap with other chronic wounds such as diabetic, venous, or traumatic ulcers [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn Nigeria, BU was first reported several decades ago, yet prevalence data remain sparse, fragmented, and geographically inconsistent [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The disease is considered endemic in several states, particularly in the southeastern and southern regions, but systematic surveillance is limited and underreporting persists [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Persistent wounds are frequent presentations in healthcare and community settings; however, their underlying causes are often inadequately investigated, leading to potential misdiagnosis and missed BU cases. Evidence from West African countries highlights the value of targeted surveys among patients with chronic or non-healing wounds as a cost-effective strategy for case detection and program planning [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eImo State, located in southeastern Nigeria, has ecological features favorable for BU transmission, including slow-moving rivers, swamps, and rural farming practices. Despite these risk factors, the burden of BU among patients with persistent wounds remains poorly documented. This knowledge gap limits the integration of BU management into broader wound care, skin NTD control strategies, and national elimination efforts.\u003c/p\u003e\u003cp\u003eThis study therefore aimed to determine the prevalence of BU among patients with persistent wounds in Imo State, Nigeria. By generating context-specific evidence, it seeks to strengthen local surveillance, enhance case detection, and contribute to global BU elimination and integrated chronic wound management.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Study setting\u003c/h2\u003e\u003cp\u003e This study was conducted in Imo State, South-Eastern Nigeria, across public and private facilities including tertiary hospitals, secondary hospitals, and high-volume primary care/wound clinics. Facilities were selected from the three senatorial zones to capture ecological variation (rural/urban and riverine/non-riverine communities).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Study design and participants\u003c/h2\u003e\u003cp\u003eWe used a cross-sectional study design. Eligible participants were patients aged 15 years and older presenting with wounds persisting for at least 4 weeks despite self-care or clinical care. Patients were excluded if they were receiving active anti-mycobacterial therapy at presentation (e.g., rifampicin for tuberculosis) or if the wound was clearly attributable to malignancy or acute trauma without chronicity. This study is a \u003cb\u003ecross-sectional survey\u003c/b\u003e (not a clinical trial).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Data collection\u003c/h2\u003e\u003cp\u003eA standardized questionnaire was administered by trained research assistants using REDCap/ODK tools. Data were collected using a structured questionnaire specifically developed for this study, adapted from WHO Buruli ulcer case-reporting tools and modified to include locally relevant socio-demographic, environmental, and health-seeking variables. The English version of the questionnaire is provided as Supplementary File 1.\u0026rdquo;\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4. Sample size determination\u003c/h2\u003e\u003cp\u003eSample size was estimated assuming a prevalence of Buruli ulcer (BU) of 3% among patients with persistent wounds, with a margin of error of 1.5% and 95% confidence level. The minimum sample size required was 267 participants. Allowing for 10% unusable samples and clustering by facility (design effect\u0026thinsp;~\u0026thinsp;1.2\u0026ndash;1.5), the final target sample size was approximately 300 participants.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5. Sampling and recruitment\u003c/h2\u003e\u003cp\u003eHealth facilities were purposively selected to ensure representation across the three senatorial zones, levels of care (tertiary, secondary, and primary), and ecological settings (rural/urban, riverine/non-riverine). Within these facilities, all patients presenting with wounds\u0026thinsp;\u0026ge;\u0026thinsp;4 weeks were screened during routine clinic days over six months. Eligible patients were consecutively enrolled until targets were met. Screening logs recorded the number assessed, enrolled, and excluded (with reasons) to minimize selection bias.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.6. Laboratory analysis\u003c/h2\u003e\u003cp\u003e Specimens were collected according to WHO guidelines. Two swabs were obtained from the undermined edges of ulcerative lesions or fine-needle aspirates for non-ulcerative lesions, and punch biopsies were taken when indicated.\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003ePrimary testing\u003c/b\u003e: IS2404 real-time PCR was performed at the National Institute of Medical Research, Lagos.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSupportive tests\u003c/b\u003e: Ziehl\u0026ndash;Neelsen microscopy, histopathology, and culture were used where feasible. Laboratory personnel were blinded to clinical suspicion.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003e2.7. Case definitions\u003c/h3\u003e\n\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eConfirmed BU\u003c/b\u003e: IS2404 PCR positive from a compatible lesion.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eProbable BU\u003c/b\u003e: Compatible lesion with positive microscopy or typical histopathology where PCR was not available.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eNon-BU wound\u003c/b\u003e: PCR negative without other evidence of BU.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e2.8. Statistical analysis\u003c/h2\u003e\u003cp\u003eData were analyzed using Stata/R. Categorical variables were summarized as frequencies and percentages, and continuous variables as means with standard deviation or medians with interquartile range.\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eThe prevalence of PCR-confirmed BU was estimated with 95% confidence intervals.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eUnivariable and multivariable logistic regression models were fitted to identify predictors of BU. Predictor variables included age, sex, senatorial zone, freshwater exposure, occupation, lesion site, and symptom duration. Robust standard errors were clustered by facility.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eSensitivity analyses included exclusion of indeterminate PCR results, use of a composite outcome (\u0026ldquo;probable\u0026thinsp;+\u0026thinsp;confirmed\u0026rdquo; BU), and multiple imputation for missing data when \u0026gt;\u0026thinsp;5%.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e2.8. Quality assurance\u003c/h2\u003e\u003cp\u003eAll research staff underwent standardized training. Specimen labeling and data entry were double-checked, and 10% of specimens were retested for quality control. External quality assurance was conducted through the National Institute of Medical Research.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e2.9. Ethical considerations\u003c/h2\u003e\u003cp\u003eEthical approval was obtained from the Imo State Ministry of Health Ethics Committee. Written informed consent was obtained from all participants after study objectives, procedures, risks, and benefits were explained in a language they understood. For participants under 18 years, assent was obtained alongside informed consent from parents or guardians. This study adhered to the principles of the Declaration of Helsinki and WHO recommendations.\u0026rdquo; All confirmed cases were referred for guideline-recommended therapy (rifampicin and clarithromycin for 8 weeks). Confidentiality was maintained in line with the Declaration of Helsinki and WHO recommendations.\u003c/p\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003ch3\u003e3.1 Demographic and Clinical Characteristics\u003c/h3\u003e\n\u003cp\u003eAmong 300 participants, most were adults aged 30\u0026ndash;59 years (51.7%) and female (53.3%). Farmers formed the largest occupational group (40.0%) and were more likely to report freshwater exposure (\u003cem\u003ep\u003c/em\u003e = 0.01). Diabetes was the most common comorbidity (55.0%), especially among those \u0026ge;50 years (OR = 1.86, 95% CI: 1.10\u0026ndash;3.14).\u003c/p\u003e\n\u003cp\u003eLesions were mainly on the lower limbs (50.0%), large (\u0026ge;5 cm, 66.7%), and chronic (\u0026ge;12 weeks, 60.0%). Delayed presentation was strongly associated with initial care outside formal health facilities (72.4% vs. 41.3%; \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). Overall, 70.0% reported freshwater contact, significantly linked to both farming and rural residence (Table 1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2. Distribution of PCR-confirmed Buruli ulcer (BU) cases\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Figure 1 shows that BU was most common among adults aged 30\u0026ndash;59 years, with fewest cases in children \u0026lt;15 years. Females were slightly more affected than males. Lesions occurred mainly on the lower limbs, followed by the upper limbs, trunk, and head/neck region.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3. Prevalence of BU among patients with persistent wounds\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Figure 2 illustrates the prevalence of BU among 300 patients with persistent wounds. One-quarter (25%, n = 75) were PCR-confirmed as BU, while the remaining 75% (n = 225) had non-BU causes, including diabetes, trauma, vascular disease, or other infections.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4. Factors associated with BU positivity\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;BU positivity was significantly associated with freshwater contact (aOR = 3.25, 95% CI: 1.45\u0026ndash;7.28), lower limb lesions (aOR = 2.80, 95% CI: 1.20\u0026ndash;6.55), and symptom duration \u0026gt;12 weeks (aOR = 4.10, 95% CI: 1.85\u0026ndash;9.08). These findings underscore ecological exposure, lesion site, and delayed diagnosis as key predictors of BU in endemic settings (Table 2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3 Logistic regression for predictors of PCR-confirmed Buruli ulcer\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLogistic regression analysis identified freshwater contact, lower limb lesions, and symptom duration greater than 12 weeks as independent predictors of PCR-confirmed Buruli ulcer. In contrast, demographic factors (age and sex) and comorbidities (diabetes and HIV) were not significantly associated with BU positivity. These findings underscore the role of ecological exposure, anatomical site of infection, and delayed presentation as key drivers of BU risk in endemic communities.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Diagnostic performance of tests for Buruli ulcer against the PCR reference standard\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Smear microscopy showed moderate sensitivity (48%) and high specificity (90%), with results available within 1 day. Histopathology (n = 60) demonstrated higher sensitivity (65%) and specificity (95%), but a longer turnaround time (median 5 days). PCR achieved 100% sensitivity and specificity, with a median turnaround of 3 days (Table 4).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study provides the first systematic assessment of BU prevalence among patients with chronic wounds in Imo State, Nigeria, and identifies key predictors of PCR-confirmed disease. We found that one in four patients with persistent wounds had BU, confirming its role as an under-recognized cause of morbidity in the region. The predominance of adult cases, particularly in the 30\u0026ndash;59-year age group, contrasts with the traditional view of BU as primarily a childhood disease and suggests that occupational and environmental exposures\u0026mdash;especially farming and freshwater contact\u0026mdash;may increase adult vulnerability [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe clinical characteristics observed\u0026mdash;large, chronic wounds predominantly affecting the lower limbs\u0026mdash;are consistent with reports from West Africa, where delayed health-seeking behavior and barriers to biomedical care exacerbate morbidity [\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The finding that 70% of patients initially sought care outside the formal health system highlights persistent gaps in awareness, trust, and access to healthcare. Similar patterns documented in Ghana and Cameroon indicate that reliance on traditional medicine contributes to diagnostic delays and poorer outcomes [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eRegression analysis identified three independent predictors of BU positivity: freshwater exposure, lower limb involvement, and wound duration longer than 12 weeks. The strong association with freshwater supports ecological evidence implicating aquatic environments as reservoirs of \u003cem\u003eM. ulcerans\u003c/em\u003e [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Lower-limb predominance likely reflects exposure during farming and household activities around rivers and swamps [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Delayed presentation emerged as the strongest predictor, emphasizing diagnostic delay as a major driver of disease progression. These findings align with World Health Organization reports identifying early detection as the cornerstone of effective BU control [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn contrast, host-related factors such as age, sex, diabetes, and HIV were not significantly associated with BU in this cohort. This suggests that environmental exposure and health-seeking behavior may play greater roles than biological susceptibility in determining infection risk [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Nonetheless, the high prevalence of comorbidities such as diabetes underscores the importance of integrated wound-care strategies, as these conditions can complicate management and delay healing even in non-BU cases [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOur diagnostic evaluation confirmed PCR as the gold standard, with high sensitivity and specificity, but its limited availability and turnaround time (median 3 days) pose challenges in resource-constrained settings [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Smear microscopy, though rapid and widely available, showed low sensitivity and risks underdiagnosis if used alone [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Histopathology offered higher accuracy but was constrained by accessibility and longer turnaround times [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. These findings underscore the need for simplified, point-of-care molecular diagnostics that combine accuracy with speed to enable timely treatment initiation [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOverall, our findings highlight BU as an important but neglected cause of chronic wounds in southeastern Nigeria. Preventive strategies should prioritize reducing unsafe freshwater exposure and promoting protective practices during farming and water-related activities. At the same time, strengthening community awareness, discouraging exclusive reliance on traditional healers, and expanding access to early diagnostic services are critical for reducing disease burden. Integrating BU screening into broader chronic wound-care programs, particularly for patients presenting with persistent lower-limb lesions, could provide an effective pathway for early detection and intervention [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eBuruli ulcer contributed significantly to the burden of chronic wounds in this study, with freshwater exposure, lower-limb involvement, and delayed presentation identified as key predictors. While PCR remains the gold standard for diagnosis, its limited availability and the low sensitivity of smear microscopy emphasize the urgent need for rapid and reliable point-of-care tests. Enhancing community awareness, encouraging early health-seeking behavior, and integrating improved diagnostic tools into routine wound care are critical to reducing BU-related morbidity and disability.\u003c/p\u003e\n\u003ch3\u003ePublic Health Implications\u003c/h3\u003e\n\u003cp\u003eThe high prevalence of Buruli ulcer among patients with chronic wounds underscores the urgency of strengthening surveillance and case-finding in endemic regions of Nigeria. Given that freshwater exposure and delayed presentation are strong predictors, targeted community education should focus on farmers, fishermen, and school-aged children who are most at risk. At the health system level, integrating rapid and accurate diagnostic tools into peripheral facilities would enable timely confirmation and treatment, reducing long-term disability. Policy responses should also prioritize environmental risk reduction, capacity-building for community health workers, and resource allocation for early detection programs. Coordinated action between government, non-governmental organizations, and community stakeholders is essential to interrupt the cycle of delayed care and improve outcomes for affected populations.\u003c/p\u003e\n\u003ch3\u003eStrengths and Limitations\u003c/h3\u003e\n\u003cp\u003eThis study was among the few systematic investigations of Buruli ulcer in southeastern Nigeria, focusing on persistent wounds and using PCR confirmation alongside multivariable regression to identify independent predictors for risk-based screening. However, its hospital-based design may not reflect the wider community burden, histopathology was limited to a subset, recall bias in reported exposures is possible, and the cross-sectional design restricts causal inference. Nevertheless, the findings offer robust evidence to strengthen early detection, diagnosis, and control of Buruli ulcer in endemic areas.\u003c/p\u003e\n\u003ch3\u003eRecommendations\u003c/h3\u003e\n\u003cp\u003eOur findings support the integration of BU surveillance into existing neglected tropical disease (NTD) programs. Expanding access to molecular and rapid diagnostic tools at peripheral facilities, alongside sustained training of health workers, is essential for timely case detection. Community-level interventions should also address behavioral and environmental risk factors, particularly freshwater exposure, while promoting early care-seeking. These combined approaches are necessary to reduce transmission, prevent disability, and improve patient outcomes in endemic regions.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003cstrong\u003eBU\u003c/strong\u003e: Buruli ulcer\u003cbr\u003e\u003cstrong\u003ePCR\u003c/strong\u003e: Polymerase chain reaction\u003cbr\u003e\u003cstrong\u003eNTDs\u003c/strong\u003e: Neglected tropical diseases\u003cbr\u003e\u003cstrong\u003eWHO\u003c/strong\u003e: World Health Organization\u003cbr\u003e\u003cstrong\u003eCI:\u0026nbsp;\u003c/strong\u003eConfidence interval\u003cbr\u003e\u003cstrong\u003eaOR\u003c/strong\u003e: Adjusted odds ratio\u003cbr\u003e\u003cstrong\u003eEQA\u003c/strong\u003e: External quality assurance\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Ethical approval was obtained from the Imo State Ministry of Health Ethics Committee. Written informed consent was obtained from all participants. For minors, parental/guardian consent and child assent were obtained.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Clinical trial number: Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;The authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;No specific funding was received for this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;OCD: Conceptualization, Methodology, Writing \u0026ndash; Original Draft.\u003cbr\u003e\u0026nbsp;CUM: Investigation, Data Curation, Laboratory Supervision.\u003cbr\u003e\u0026nbsp;Both authors: Formal Analysis, Writing \u0026ndash; Review \u0026amp; Editing.\u003cbr\u003e\u0026nbsp;All authors read and approved the final manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgements\u003c/h2\u003e\n\u003cp\u003eWe thank participating patients and families; clinical and laboratory teams at Federal Medical Center, Umuagwo Specialist Hospital, and Ejemekwuru Health Center; Imo State Ministry of Health; and community health volunteers. We acknowledge National Institute of Medical Research, Lagos, for EQA support\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWorld Health Organization. Buruli ulcer (Mycobacterium ulcerans infection). Geneva: WHO. 2023. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.who.int/news-room/fact-sheets/detail/buruli-ulcer-(mycobacterium-ulcerans-infection)\u003c/span\u003e\u003cspan address=\"https://www.who.int/news-room/fact-sheets/detail/buruli-ulcer-(mycobacterium-ulcerans-infection)\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYotsu RR. Buruli ulcer: clinical and epidemiological aspects. Trop Med Health. 2018;46:11.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMerritt RW, Walker ED, Small PLC, Wallace JR, Johnson PDR, Benbow ME, et al. Ecology and transmission of \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e. Emerg Infect Dis. 2010;16(3):355\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTai A, Athan E, Friedman ND, Hughes AJ. Buruli ulcer: an Australian perspective. Med J Aust. 2008;188(5):273\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSimpson H, Deribe K, Tabah EN, Peters A, Molyneux D. Mapping the global distribution of Buruli ulcer: a systematic review with evidence consensus. Lancet Glob Health. 2019;7(7):e912\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMarsollier L, Aubry J, Coutanceau E, Andr\u0026eacute; JP, Small PLC, Milon G, et al. Colonization of the salivary glands of Naucoris cimicoides by \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e requires host plasmatocytes and is a model for transmission by insect bite. Infect Immun. 2005;73(9):5762\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJunghanss T, Johnson RC, Pluschke G. Mycobacterium ulcerans disease. In: Farrar J, Hotez PJ, Junghanss T, Kang G, Lalloo D, White NJ, editors. Manson\u0026rsquo;s Tropical Diseases. 23rd ed. Elsevier; 2014. pp. 519\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVincent QB, Ardant MF, Marsollier L, Chauty A, Alcais A, Franco E, et al. Clinical epidemiology of laboratory-confirmed Buruli ulcer in Benin: a cohort study. Lancet Glob Health. 2014;2(7):e422\u0026ndash;30.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNienhuis WA, Stienstra Y, Thompson WA, Awuah PC, Abass KM, Tuah W, et al. Antimicrobial treatment for early, limited \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e infection: a randomized controlled trial. Lancet. 2010;375(9715):664\u0026ndash;72.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWadagni AC, Barogui YT, Johnson RC, Sopoh GE, Affolabi D, Gbovi J, et al. Delays in seeking care for Buruli ulcer in Benin. PLoS Negl Trop Dis. 2019;13(5):e0007256.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOluwasanmi JO, Solankee TF, Olurin EO, Itayemi SO, Alabi GO, Lucas AO. Mycobacterium ulcerans (Buruli) skin ulceration in Nigeria. Am J Trop Med Hyg. 1976;25(1):122\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eUkwaja KN, Meka AO, Chukwu JN, Kayode PO, Ekeke N et al. Huis In\u0026rsquo;t Veld D,. Buruli ulcer in Nigeria: a pilot case study. Trans R Soc Trop Med Hyg. 2016;110(7):460\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChukwu JN, Meka AO, Nwafor CC, Oshi DC, Madichie NO, Ekeke N, et al. Buruli ulcer in Nigeria: results of a pilot case study in three rural districts. Infect Dis Poverty. 2017;6(1):12.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSopoh GE, Dossou AD, Johnson RC, Barogui YT, Makoutode M, Anagonou SY, et al. Buruli ulcer surveillance, Benin, 2003\u0026ndash;2005. Emerg Infect Dis. 2010;16(7):1204\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDebacker M, Aguiar J, Steunou C, Zinsou C, Meyers WM, Gu\u0026eacute;d\u0026eacute;non A, et al. Mycobacterium ulcerans disease: role of age and gender in incidence and morbidity. Trop Med Int Health. 2004;9(12):1297\u0026ndash;304.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eR\u0026ouml;ltgen K, Pluschke G. Epidemiology and disease burden of Buruli ulcer: a review. Res Rep Trop Med. 2015;6:59\u0026ndash;73.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAckumey MM, Gyapong M, Pappoe M, Maclean CK, Weiss MG. Illness meanings and experiences for pre-ulcer and ulcer conditions of Buruli ulcer in the Ga-West and Ga-South municipalities of Ghana. BMC Public Health. 2012;12:264.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAhorlu CK, Koka E, Yeboah-Manu D, Lamptey I, Ampadu EO. Enhancing Buruli ulcer control in Ghana through social interventions: a case study from the Obom sub-district. BMC Public Health. 2013;13:59.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eStienstra Y, van der Graaf WT, Asamoa K, van der Werf TS. Beliefs and attitudes toward Buruli ulcer in Ghana. Am J Trop Med Hyg. 2002;67(2):207\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMulder AA, Boerma RP, Barogui YT, Zinsou C, Johnson RC, Gbovi J, et al. Healthcare seeking behaviour for Buruli ulcer in Benin: a model to capture therapy choice of patients and healthy community members. Trans R Soc Trop Med Hyg. 2008;102(9):912\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAlferink M, Sopoh GE, Agossadou C, Barogui YT, Zinsou C, Johnson RC, et al. Healthcare seeking behaviour and diagnostic delays for Buruli ulcer in Benin: a cross-sectional study. BMC Public Health. 2013;13:501.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWilliamson HR, Benbow ME, Nguyen KD, Beachboard DC, Kimbirauskas RK, McIntosh MD, et al. Distribution of \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e in Buruli ulcer endemic and non-endemic aquatic sites in Ghana. PLoS Negl Trop Dis. 2008;2(3):e205.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMarion E, Chauty A, Yeramian E, Babonneau J, Kempf M, Marsollier L. A case of guilt by association: \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e toxin mycolactone impairs wound healing through cytotoxicity and immune modulation. PLoS Pathog. 2016;12(7):e1005473.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eConverse PJ, Almeida DV, Nuermberger EL, Grosset JH. \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e infection in the mouse: dose\u0026ndash;response studies with rifampin, streptomycin, amikacin, and clarithromycin. Antimicrob Agents Chemother. 2011;55(1):310\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWorld Health Organization. Treatment of Mycobacterium ulcerans disease (Buruli ulcer): guidance for health workers. Geneva: WHO; 2012.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRaghunathan PL, Whitney EA, Asamoa K, Stienstra Y, Taylor TH Jr, Amofah GK, et al. Risk factors for Buruli ulcer disease (Mycobacterium ulcerans infection): results from a case\u0026ndash;control study in Ghana. Clin Infect Dis. 2005;40(10):1445\u0026ndash;53.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEddyani M, Sopoh GE, Brun LV, Kestens L, Rogge D, Barogui Y, et al. Buruli ulcer and co-infection with HIV. Emerg Infect Dis. 2014;20(11):1969\u0026ndash;76.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFyfe JA, Lavender CJ, Johnson PD, Globan M, Sievers A, Azuolas J, et al. Development and application of two multiplex real-time PCR assays for detection of \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e in clinical and environmental samples. Appl Environ Microbiol. 2007;73(15):4733\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePhillips R, Horsfield C, Kuijper S, Lartey A, Tetteh I, Etuaful S, et al. Sensitivity of PCR targeting IS2404 for diagnosis of Buruli ulcer. J Clin Microbiol. 2005;43(9):3650\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePortaels F, Meyers WM, Ablordey A, Castro AG, Chemlal K, de Rijk P, et al. First cultivation and characterization of \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e from the environment. Lancet. 1999;353(9157):986\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMitj\u0026agrave; O, Marks M, Bertran L, Kollie K, Argaw D, Fahal AH, et al. Integrated control and management of skin neglected tropical diseases in sub-Saharan Africa: addressing an emerging public-health and research priority. PLoS Negl Trop Dis. 2017;11(1):e0005136.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1 to 4 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Buruli ulcer, Mycobacterium ulcerans, persistent wounds, Nigeria, PCR, neglected tropical diseases","lastPublishedDoi":"10.21203/rs.3.rs-7470652/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7470652/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eBuruli ulcer (BU), caused by \u003cem\u003eMycobacterium ulcerans\u003c/em\u003e, is a neglected tropical disease presenting with chronic necrotizing skin lesions. In Nigeria, its role in the burden of persistent wounds is poorly understood due to diagnostic challenges and overlapping clinical presentations.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eWe conducted a multisite cross-sectional study among patients with wounds persisting\u0026thinsp;\u0026ge;\u0026thinsp;4 weeks across healthcare facilities in Imo State, Nigeria. Socio-demographic, clinical, and exposure data were collected using standardized questionnaires. Wound specimens were tested with IS2404 real-time PCR (reference standard), smear microscopy, and histopathology (subset). Logistic regression identified independent predictors of BU.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eOf 300 participants, 75 (25.0%) had PCR-confirmed BU. Most were adults aged 30\u0026ndash;59 years (53.4%), farmers (40.0%), and individuals reporting freshwater exposure (70.0%). Lesions were mainly on the lower limbs (53.3%), large (\u0026ge;\u0026thinsp;5 cm, 66.7%), and chronic (\u0026ge;\u0026thinsp;12 weeks, 60.0%). Seventy percent initially sought care outside the formal health system. Predictors of BU included freshwater contact (aOR\u0026thinsp;=\u0026thinsp;3.25, 95% CI: 1.45\u0026ndash;7.28), lower limb lesions (aOR\u0026thinsp;=\u0026thinsp;2.80, 95% CI: 1.20\u0026ndash;6.55), and symptom duration\u0026thinsp;\u0026gt;\u0026thinsp;12 weeks (aOR\u0026thinsp;=\u0026thinsp;4.10, 95% CI: 1.85\u0026ndash;9.08). Smear microscopy showed low sensitivity (48%) but high specificity (90%); histopathology demonstrated sensitivity of 65% and specificity of 95%. PCR achieved 100% accuracy with a median turnaround of 3 days.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eBU is a substantial but under-recognized cause of persistent wounds in southeastern Nigeria. Early recognition, risk-based screening, and deployment of rapid molecular tests at peripheral facilities are essential to improving detection and outcomes.\u003c/p\u003e","manuscriptTitle":"Survey on the Prevalence of Buruli Ulcer among Patients with Persistent Wounds in Imo State, Nigeria","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-08 16:03:05","doi":"10.21203/rs.3.rs-7470652/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1e825311-7341-4129-a06e-4337a4bf05f6","owner":[],"postedDate":"October 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-16T16:38:23+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-08 16:03:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7470652","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7470652","identity":"rs-7470652","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}