Estimation of Seropositivity to Burkholderia pseudomallei Among Family Members of Melioidosis Patients by Indirect Hemagglutination Assay

Estimation of Seropositivity to Burkholderia pseudomallei Among Family Members of Melioidosis Patients by Indirect Hemagglutination Assay | 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 Estimation of Seropositivity to Burkholderia pseudomallei Among Family Members of Melioidosis Patients by Indirect Hemagglutination Assay Soumi Chowdhury, Vandana Kalwaje Eshwara, Chiranjay Mukhopadhyay This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6988004/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: Melioidosis, caused by Burkholderia pseudomallei , is a significant public health concern in tropical regions. This study aimed to identify predictors of high IHA titers among family members of culture-proven melioidosis patients, providing valuable insights into its epidemiology. Methods: A cross-sectional study was conducted at Kasturba Hospital, Manipal, India from June 2020 to December 2022; enrolled adult family members of melioidosis patients without recent signs of infection or antibiotic exposure. Blood samples were tested for anti- B. pseudomallei antibodies using the indirect hemagglutination (IHA) assay. Socio-demographic and lifestyle data were collected via detailed questionnaires. Logistic regression identified predictors of seropositive individuals (IHA titer > 40), with results presented as prevalence odds ratios (POR) and 95% confidence intervals (CI). Results: Among the 246 participants (mean age 46.1 years), the seroprevalence rate was 8.13%. Significant predictors of high IHA titers included older age (POR: 1.03 per year; CI: 0.995-1.08; p=0.092), female gender (POR: 0.186; CI: 0.0588-0.500; p=0.001), occupation as a farmer (POR: 3.27; CI: 1.30-8.69; p=0.019), and activities like walking in fields (POR: 7.20; CI: 2.27-34.3; p = 0.002) or rice fields (POR: 3.85; CI: 1.31-12.1; p=0.010). Conversely, smoking (POR: 0.274; CI: 0.0955-0.723; p<0.001) and washing clothes in the river (POR: 0.118; CI: 0.0321-0.380; p=0.001) showed a decreased likelihood of high IHA titers. Conclusions: These findings highlight key demographic and lifestyle factors associated with high IHA titers among family members of melioidosis patients, guiding targeted public health interventions to reduce B. pseudomallei exposure. Trial registered: This study has been registered in Clinical Trial Registry India; CTRI registration number: CTRI/2020/06/025663; CTRI registration date: 02/06/2020. Infectious Diseases Epidemiology Melioidosis Burkholderia pseudomallei Indirect Hemagglutination Assay family members India Figures Figure 1 Background Background Melioidosis, caused by B. pseudomallei , is an underreported tropical disease (1). It ranges from asymptomatic to severe forms like septicaemia and pneumonia (1-3), transmitted via inhalation, ingestion or direct contact with contaminated soil and water (2,4). In India, especially Karnataka and Tamil Nadu reported melioidosis cases have surged (5), but true prevalence is likely higher due to clinician awareness issues and frequent misdiagnoses, leading to widespread seropositivity (6,7). Exposure can result in either prolonged periods without symptoms or progression to severe disease with a range of clinical presentations (1,3,4). Most commonly, seroconversion occurs without active infection (4). Melioidosis often presents as community-acquired pneumonia with sepsis but can also manifest as skin infections, abscesses, neurological infections, bone and joint infections, and pericardial effusion (1-3). Those with diabetes, renal disease, or immunosuppression are at higher risk of severe illness and mortality (1,2,8), with septic shock cases showing a 41% mortality rate (9-13). A seroprevalence study in the Udupi district showed a 29% exposure rate among healthy individuals (4). However, data on seropositivity among family members of melioidosis patients is lacking. To fill this gap, our study aims to estimate the seroprevalence rate of melioidosis among family members of melioidosis-positive patients. Rationale Considering the significant public health implications of melioidosis, particularly in endemic regions with close community interactions, it is crucial to explore the extent of exposure among family members of confirmed cases. Understanding the seroprevalence of antibodies against B. pseudomallei within these groups can provide insights into potential risk factors and help identify high-risk populations. The Indirect Hemagglutination Assay (IHA), a sensitive and specific serological test, is an effective tool for detecting prior exposure to B. pseudomallei , yielding valuable data for both epidemiological surveillance and preventive measures. Methods Study design A cross-sectional study was conducted at Kasturba Hospital, Manipal, India, from June 2020 to December 2022. Adult family members of culture-proven melioidosis patients were enrolled, excluding those with recent infections, hospitalisations, or antibiotic exposure. Ethical approval was obtained from the Ethics Committee of Kasturba Medical College and Kasturba Hospital (reference number 77/2020). Participants or their authorized representatives provided written informed consent prior to participation. Sample Collection Blood samples were collected from each family member of confirmed melioidosis cases, and serum was separated for further analysis. A face-to-face questionnaire, extensively field-tested, gathered comprehensive data on socio-demographic factors, occupations, activities involving environmental exposure, lifestyles, travel history, and existing therapy. Serum samples were stored at -80°C until processing. Subsequently, these samples were tested for antibodies against B. pseudomallei antigen using the indirect hemagglutination (IHA) assay. Polysaccharide antigens for the assay were prepared in the microbiology laboratory from B. pseudomallei clinical isolates, following the methodology outlined by Peacock and Wuthiekanun (14). The optimal antigen dilution was determined by titrating against known positive serum samples provided by the Mahidol Oxford Research Unit in Bangkok, Thailand (15). A positive result was defined as a titer of ≥1:40, indicating seropositive individuals. Statistical analysis Logistic regression analysed predictors of seropositive (IHA titer > 40) versus seronegative (<40). Independent variables included demographics, occupations, and lifestyle factors. Separate models were fitted for each variable, with prevalence odds ratios (POR) and 95% confidence intervals (CI) assessing associations. Statistical significance was determined at p < 0.05, summarized in Table 1. Analyses were performed using R software, with the "glm" function for binomial logistic regression and the "broom" package for organizing results, including POR, standard errors, z-values, p-values, and CI. Results We recruited 246 family members of individuals diagnosed with melioidosis, aged between 18 and 80 years, upon obtaining written informed consent. The study revealed an overall seroprevalence rate of 8.13% (n=20), with 56.9% of participants showing no evidence of seropositivity and 23.9% displaying antibody titers of 1:20 ( figure 1 ). Table 1 provides a summary of the clinical characteristics of participants based on their seropositivity status, along with the associated POR and CI. The study participants with IHA titer > 40 were predominantly female (75%) with a mean age of 49.35 years (SD + 11.31) and IHA titer 40 (seropositive individuals) compared to<40 (seronegative individuals). Age showed a positive association, suggesting that each additional year increased the odds of seropositivity by 3% (POR:1.03; 95% CI:0.995-1.08; p=0.092). Gender was also significant, with males having significantly lower seropositivity odds than females (POR:0.186; 95% CI:0.0588-0.500; p=0.001). Occupation emerged as a crucial factor; farmers had significantly higher odds of being seropositive (POR:3.27; 95% CI:1.30-8.69; p=0.019), as did professionals (mostly teacher, driver) (POR:4.46; 95% CI:1.15-14.6; p=0.018). However, there is no seropositivity difference between farmers and non-farmers. Lifestyle choices such as smoking and alcohol consumption were also influential. Smokers had lower odds of seropositivity (POR:0.274; 95% CI:0.0955-0.723; p<0.001), while alcohol consumers had higher odds (POR:3.27; 95% CI:1.19-9.11; p=0.022), though the alcohol consumers were modest. Activities like walking in fields and rice fields were strongly associated with increased odds of seropositivity (POR:7.20; 95% CI:2.27-34.3; p=0.002 and POR:3.85; 95% CI:1.31-12.1; p=0.010, respectively). Conversely, washing clothes in the river was linked with lower odds of seropositivity (POR:0.118; 95% CI:0.0321-0.380; p=0.001). These findings underscore the demographic and lifestyle factors contributing to seropositive status, which could guide targeted public health interventions. Discussion India, a hotspot for melioidosis, exhibiting significant isolation of B. pseudomallei from soil and water (4). This study found an 8.13% seroprevalence among family members of melioidosis patients, highlighting notable exposure. The findings on demographic and lifestyle factors provide valuable insights for informing targeted public health interventions. The Indirect Hemagglutination Assay (IHA), introduced in 1965, is valued for its simplicity, speed, and effectiveness in detecting antibodies (16,17). However, in melioidosis-endemic regions, IHA's specificity and sensitivity are poor (18). Our study used a cut-off titer of ≥1:40 to enhance specificity, aligning with research from Southern India (4). While this increases specificity, it can reduce sensitivity (19). Conversely, a lower cut-off, such as ≥1:10, increases sensitivity, as seen in a Puducherry study where seropositivity rose to 25.6% (20). Participants with a positive IHA titer (≥1:40) were predominantly female and older, aligning with prior research suggesting age and gender influence susceptibility to infectious diseases (4). The study found an overall seroprevalence of 8.13% (n=20), with 56.9% showing no seropositivity. Antibody titers of 1:20 were found in 23.9% (n=59) of participants, while 10.5% (n=26) had titers of 1:10. These results are consistent with previous findings from Southern India, where a seroprevalence rate of 29% was reported using a titer threshold of 1:20 (4), and from Puducherry, where seropositivity was found in 19.8% of participants using a titer of ≥1:20 (20). Comparisons to studies from other endemic regions vary depending on the antibody titer threshold. For instance, in Thailand, seroprevalence ranged from 6.4% to 31.8%, depending on the titer cutoff used (21). Similarly, Vietnam reported rates between 6.4% and 31.8% (23), and Bangladesh reported a seroprevalence of 28.9% (24). However, in Australia, studies have typically used higher titer cutoffs, such as 1:40 or above, explaining the lower observed rates of around 3% (22). The difference in thresholds complicates direct comparison, but the broader exposure context in regions with endemic melioidosis remains relevant. In Southern India, farmers face higher melioidosis risks due to frequent contact with the bacterium. The study found higher seropositivity among farmers, consistent with findings from Puducherry, Bangladesh, and Thailand (20,24), where farmers are 4.6 times more likely to test positive (19). However, one Bangladesh study reported no significant difference between farmers and non-farmers (24). These findings highlight farmers' increased vulnerability to melioidosis with activities involving direct contact with soil (walking in fields, rice paddies and gardening) were strongly associated with seropositivity. Vandana et al. found that gardening and river water sources increase exposure to B. pseudomallei (4). However, our study suggests a lower correlation between washing clothes in rivers and IHA titers, possibly reflecting increased awareness of melioidosis transmission risks among the population. Public health education campaigns and local initiatives in endemic regions may have successfully informed communities about the dangers of contact with contaminated water sources, such as rivers. As a result, behavioural changes, including reducing or avoiding practices like washing clothes in these rivers, may have decreased exposure to the bacterium, leading to lower antibody titers in individuals. These shifts in behaviour highlight the importance of awareness in mitigating risk and controlling potential exposure. In Taiwan, walking barefoot and exposure to flooding increased melioidosis risk (25), whereas a study in Puducherry found no significant correlation between seropositivity and smoking, alcohol, water proximity, gardening, or footwear (20). The association between age and seropositivity is unclear. Previous research in Southern India found no significant variations among adults (4). However, our current study shows higher seropositivity in those aged 41-50, suggesting recurrent exposure, aligning with findings from Bangladesh (26) and Puducherry (20), which show higher rates in older age groups. In contrast, Thailand shows increasing seropositivity among children with age (27-29), while Australia reports decreasing seroprevalence with age (30). Gender-specific seropositivity rates vary across studies, with Australia (6) and Bangladesh (26) reporting comparable rates between sexes, while our investigation found higher seropositivity in females. This discrepancy is notable as melioidosis predominantly affects males. Vandana et al. (4) suggested that behavioural patterns and environmental exposures might explain this difference, with females potentially seroconverting without symptoms due to fewer outdoor activities. Ongoing serosurveillance among high-risk individuals, particularly farmers in agricultural regions, is essential. These findings can inform targeted surveillance and environmental control measures and aid public health policy decisions. Targeted public health interventions could include customized educational campaigns to raise awareness about melioidosis and preventive measures, particularly for high-risk groups such as agricultural workers and individuals with frequent exposure to contaminated soil and water. Additionally, improving access to diagnostic and treatment facilities in affected areas and implementing regular screening programs for at-risk populations could help in the early detection and management of the disease. By focusing these interventions on individuals with identified risk factors, public health efforts can more effectively reduce the incidence and impact of melioidosis. This study's limitations are excluding healthy children, limiting younger age group seropositivity assessment, and the Indirect Haemagglutination Assay's (IHA) variable sensitivity and specificity. Future research should build on these findings by utilizing more precise diagnostic methods. Advanced molecular techniques, such as polymerase chain reaction (PCR) for detecting B. pseudomallei DNA, enzyme-linked immunosorbent assays (ELISA) for improved antibody detection, or whole-genome sequencing (WGS) for highly specific pathogen identification, could offer more accurate diagnoses. These methods would help overcome the limitations of serological tests, such as IHA, in terms of specificity and sensitivity, providing more reliable data for both epidemiological surveillance and patient management in melioidosis-endemic regions. Conclusion In conclusion, this study highlights the impact of demographic and lifestyle factors on melioidosis seroprevalence and symptomatic status among family members of positive cases. Early detection and proactive management are crucial for controlling the disease within affected communities. Identified risk factors, including gender, occupation, and environmental exposures, can guide targeted public health strategies in endemic regions. Further research is needed to explore the mechanisms behind these correlations and develop effective interventions to reduce disease burden and enhance understanding of melioidosis transmission dynamics within households. Declarations Ethics approval and consent to participate Ethical approval was obtained from the Kasturba Medical College and Kasturba Hospital Ethics Committee (reference number 77/2020) along with the informed consent of all study participants. Consent of publications All authors have approved of the manuscript and agree with the submission. Data availability and materials All data underlying the results are available in the article; no additional source data are required. Competing interest The authors report there are no competing interests to declare. Funding This study was supported by the Indian Council of Medical Research (ICMR), New Delhi, India to C.M [Grant number 2020-1381]. Department of Science and Technology also supported this study to S.C [Grant number DST/INSPIRE/03/2018/003582]. The funders had no role in study design, data collection and analysis, preparation of the manuscript, or the decision to publish. Author contributions S.C. designed the study, performed sample and clinical data collection, interpreted the analysis, and wrote the manuscript. V.K.E. provided intellectual input and reviewed the manuscript. C.M. designed the study, assisted with the results, writing and reviewed the manuscript. Acknowledgements We are grateful to all patients’ family members who participated in the study and all staff involved in the data collection. We thank Mr Venkat Abhiram Earny for helping with the collection and processing of sheep blood for this study. References Cheng AC, Currie BJ. Melioidosis: epidemiology, pathophysiology, and management. Clin Microbiol Rev 2005; 18:383–416. Currie BJ, Fisher DA, Howard DM, Burrow JN, Lo D, Selva-Nayagam S, et al. Endemic melioidosis in tropical northern Australia: a 10-year prospective study and review of the literature. Clin Infect Dis. 2000; 31:981–986. Currie BJ. 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Clinical demographics among seropositive and seronegative individuals: Seropositive (IHA > 40) = 20 Seronegative (IHA<40) = 226 P-value Crude POR (95%CI) Age (mean (SD)) 49.35 (11.31) 44.56 (12.20) 0.092 1.03 (0.995-1.08) Age categories (%) 18-30 1 (5.0) 27 (11.9) 0.001 0.037 (0.018-0.076) 31-40 6 (30.0) 96 (42.5) 0.634 1.687 (0.825-3.449) 41-50 3 (15.0) 25 (11.1) 0.332 3.240(1.312-7.993) >50 5 (25.0) 78 (34.5) 0.244 3.462(1.073-11.202) Gender (%) Male sex 5 (25) 145 (64.2) 0.001 0.186 (0.058-0.500) Female sex 15 (75) 81 (35.8) 0.001 5.368 (0.186 - 0.500) Major occupational group, n (%) Farmer 12(60) 71(31.4) 0.019 3.27 (1.30-8.69) Non-Farmer 8(40) 155 (68.5) 1 Skill level job (%) Professionals 4 (20) 12 (5.3) 0.018 4.46 (1.15-14.6) Sales worker 0 (0) 8 (3.5) 0.843 - Production worker 1 (5) 44 (19.4) 0.193 0.23 (0.003-4.26) Agricultural worker 2 (10) 26 (11.5) 1.000 0.861 (0.065-5.34) Other work 1 (5) 65 (28.7) 0.042 0.143 (0.003-2.59) Smoking, n (%) Yes 9 (45) 169 (74.7) <0.001 0.274 (0.095-0.723) No 6 (30) 52 (23) 1 Refused to answer 5 (25) 5 (2.2) Alcohol consumption, n (%) Yes 10 (50) 67 (29.6) 0.022 3.27 (1.19-9.11) No 5 (25) 146 (64.6) 1 Refused to answer 5 (25) 13 (5.7) Walking in fields, n (%) Yes 15 (75) 59 (26.1) 0.002 7.20 (2.27-34.3) No 5 (25) 167 (73.8) 1 Walking in the rice field, n (%) Yes 11 (55) 57 (25.2) 0.010 3.85 (1.31-12.1) No 9 (45) 169 (74.7) 1 Gardening, n (%) Yes 8 (40) 43 (19) 0.054 2.72 (0.976-7.58) No 12 (60) 183 (80.9) 1 Wash clothes in the river, n (%) Yes 6 (30) 159 (70.3) 0.001 0.118 (0.032-0.380) No 14 (70) 67 (29.6) 1 Wear footwear, n (%) Always 14 (70) 189 (83.6) 0.218 1.09 (0.236-4.92) Sometimes 6 (30) 37 (16.3) 0.218 2.02 (0.398-9.76) Diabetes, n (%) Yes 15 (75) 168 (74) 0.843 1.15 (0.141-10.3) No 4 (20) 39 (17.2) 1 Don’t know 1 (5) 19 (8.4) Other Comorbidities, n (%) Yes 6 (30) 54 (23.8) <0.001 1.36 (0.310-6.34) No 7 (35) 172 (76.1) 1 Additional Declarations The authors declare no competing interests. Supplementary Files AdditionalfileSTROBEchecklist.pdf Supporting Information S1 Checklist. STROBE statement—Checklist of items that should be included in reports of cross-sectional studies. Supplementaryfile1.pdf Supplementary file 1. Questionnaire on Melioidosis 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6988004","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":477172703,"identity":"1e5a89a8-6055-4271-8ff9-0d840fb64632","order_by":0,"name":"Soumi Chowdhury","email":"","orcid":"","institution":"Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India","correspondingAuthor":false,"prefix":"","firstName":"Soumi","middleName":"","lastName":"Chowdhury","suffix":""},{"id":477172794,"identity":"45cd4d4a-d118-4aff-874b-6e4c5c2a360b","order_by":1,"name":"Vandana Kalwaje Eshwara","email":"","orcid":"","institution":"Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India","correspondingAuthor":false,"prefix":"","firstName":"Vandana","middleName":"Kalwaje","lastName":"Eshwara","suffix":""},{"id":477176349,"identity":"ee097ed1-d368-403f-abde-7a61d725bf18","order_by":2,"name":"Chiranjay Mukhopadhyay","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAElEQVRIiWNgGAWjYDACCcYGIMkGYjI+ABI8DAzMDVABwlqYDSBaGAlpQTDZoGwCWvhnN7d9+LmDT97gAHda1Y2aOzLm7AcbGD6UHcZtyZ2DzTN7z7AZbjjAu+12zrFnPJY9iQ2MM87h1mIgkdjMwNvGxgjRwnaYx+BAYgMzbxt+LYx/29jsQVqKc/4BtZx/2MD8l4AWoJlsiSAtzLltQC03gLYw4tEicQOoRbaNLXnmYd7N0rl9h3ksZzxsONhzLh2nFv4Z6Y8Z37Yds+073rvxc863w/bm/MkHH/wos8apBQqOMSjAXAKKzwOE1ANBDYN8A5KWUTAKRsEoGAXIAADPKFq/xFyN9wAAAABJRU5ErkJggg==","orcid":"","institution":"Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India","correspondingAuthor":true,"prefix":"","firstName":"Chiranjay","middleName":"","lastName":"Mukhopadhyay","suffix":""}],"badges":[],"createdAt":"2025-06-27 05:09:27","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":true,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-6988004/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6988004/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85756366,"identity":"f2ae68d0-dfee-4f29-9bb4-3d3a77eaf8fa","added_by":"auto","created_at":"2025-07-01 10:49:06","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":33727,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDistribution of IHA titers among melioidosis patients’ family members\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6988004/v1/8a0d850d5a3e1f9b829aaba4.png"},{"id":85758221,"identity":"250c6f1f-b69b-4e07-b605-d4e0f8f780f6","added_by":"auto","created_at":"2025-07-01 11:05:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":814246,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6988004/v1/5bb6c9fc-ce2a-483a-b0ad-ef03069fca07.pdf"},{"id":85756365,"identity":"9410eeeb-90ea-491c-8eea-2be24c010271","added_by":"auto","created_at":"2025-07-01 10:49:06","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":87896,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSupporting Information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eS1 Checklist. STROBE statement—Checklist of items that should be included in reports of cross-sectional studies.\u003c/p\u003e","description":"","filename":"AdditionalfileSTROBEchecklist.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6988004/v1/ce71ae12a2ce0b3a37d2081b.pdf"},{"id":85756370,"identity":"9569b162-3de4-44b0-85ad-8e9fd68fbb17","added_by":"auto","created_at":"2025-07-01 10:49:06","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":168946,"visible":true,"origin":"","legend":"\u003cp\u003eSupplementary file 1. Questionnaire on Melioidosis\u003c/p\u003e","description":"","filename":"Supplementaryfile1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6988004/v1/3d527392068b83d18785d58d.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eEstimation of Seropositivity to \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eBurkholderia pseudomallei\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e Among Family Members of Melioidosis Patients by Indirect Hemagglutination Assay\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Background","content":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMelioidosis, caused by \u003cem\u003eB. pseudomallei\u003c/em\u003e, is an underreported tropical disease (1). It ranges from asymptomatic to severe forms like septicaemia and pneumonia (1-3), transmitted via inhalation, ingestion or direct contact with contaminated soil and water (2,4). In India, especially Karnataka and Tamil Nadu reported melioidosis cases have surged (5), but true prevalence is likely higher due to clinician awareness issues and frequent misdiagnoses, leading to widespread seropositivity (6,7). Exposure can result in either prolonged periods without symptoms or progression to severe disease with a range of clinical presentations (1,3,4). Most commonly, seroconversion occurs without active infection (4). Melioidosis often presents as community-acquired pneumonia with sepsis but can also manifest as skin infections, abscesses, neurological infections, bone and joint infections, and pericardial effusion (1-3). Those with diabetes, renal disease, or immunosuppression are at higher risk of severe illness and mortality (1,2,8), with septic shock cases showing a 41% mortality rate (9-13). A seroprevalence study in the Udupi district showed a 29% exposure rate among healthy individuals (4). However, data on seropositivity among family members of melioidosis patients is lacking. To fill this gap, our study aims to estimate the seroprevalence rate of melioidosis among family members of melioidosis-positive patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRationale\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Considering the significant public health implications of melioidosis, particularly in endemic regions with close community interactions, it is crucial to explore the extent of exposure among family members of confirmed cases. Understanding the seroprevalence of antibodies against \u003cem\u003eB. pseudomallei\u003c/em\u003e within these groups can provide insights into potential risk factors and help identify high-risk populations. The Indirect Hemagglutination Assay (IHA), a sensitive and specific serological test, is an effective tool for detecting prior exposure to \u003cem\u003eB. pseudomallei\u003c/em\u003e, yielding valuable data for both epidemiological surveillance and preventive measures.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA cross-sectional study was conducted at Kasturba Hospital, Manipal, India, from June 2020 to December 2022. Adult family members of culture-proven melioidosis patients were enrolled, excluding those with recent infections, hospitalisations, or antibiotic exposure. Ethical approval was obtained from the Ethics Committee of Kasturba Medical College and Kasturba Hospital (reference number 77/2020). Participants or their authorized representatives provided written informed consent prior to participation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSample Collection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBlood samples were collected from each family member of confirmed melioidosis cases, and serum was separated for further analysis. A face-to-face questionnaire, extensively field-tested, gathered comprehensive data on socio-demographic factors, occupations, activities involving environmental exposure, lifestyles, travel history, and existing therapy. Serum samples were stored at -80°C until processing. Subsequently, these samples were tested for antibodies against \u003cem\u003eB. pseudomallei\u003c/em\u003e antigen using the indirect hemagglutination (IHA) assay. Polysaccharide antigens for the assay were prepared in the microbiology laboratory from \u003cem\u003eB. pseudomallei\u0026nbsp;\u003c/em\u003eclinical isolates, following the methodology outlined by Peacock and Wuthiekanun (14). The optimal antigen dilution was determined by titrating against known positive serum samples provided by the Mahidol Oxford Research Unit in Bangkok, Thailand (15). A positive result was defined as a titer of ≥1:40, indicating seropositive individuals.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLogistic regression analysed predictors of seropositive (IHA titer\u003cu\u003e\u0026gt;\u003c/u\u003e40) versus seronegative (\u0026lt;40). Independent variables included demographics, occupations, and lifestyle factors. Separate models were fitted for each variable, with prevalence odds ratios (POR) and 95% confidence intervals (CI) assessing associations. Statistical significance was determined at p \u0026lt; 0.05, summarized in Table 1. Analyses were performed using R software, with the \"glm\" function for binomial logistic regression and the \"broom\" package for organizing results, including POR, standard errors, z-values, p-values, and CI.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u0026nbsp;We recruited 246 family members of individuals diagnosed with melioidosis, aged between 18 and 80 years, upon obtaining written informed consent. The study revealed an overall seroprevalence rate of 8.13% (n=20), with 56.9% of participants showing no evidence of seropositivity and 23.9% displaying antibody titers of 1:20 (\u003cstrong\u003efigure 1\u003c/strong\u003e). Table 1 provides a summary of the clinical characteristics of participants based on their seropositivity status, along with the associated POR and CI.\u0026nbsp;The study participants with IHA titer\u003cu\u003e\u0026gt;\u003c/u\u003e40 were predominantly female (75%) with a mean age of 49.35 years (SD \u003cu\u003e+\u003c/u\u003e11.31) and IHA titer\u0026lt;40 with a mean age of 44.56 years (SD \u003cu\u003e+\u003c/u\u003e12.20).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe logistic regression analysis identified several significant factors associated with having an IHA titer\u003cu\u003e\u0026gt;\u003c/u\u003e40 (seropositive individuals) compared to\u0026lt;40 (seronegative individuals). Age showed a positive association, suggesting that each additional year increased the odds of seropositivity by 3% (POR:1.03; 95% CI:0.995-1.08; p=0.092). Gender was also significant, with males having significantly lower seropositivity odds than females (POR:0.186; 95% CI:0.0588-0.500; p=0.001). Occupation emerged as a crucial factor; farmers had significantly higher odds of being seropositive (POR:3.27; 95% CI:1.30-8.69; p=0.019), as did professionals (mostly teacher, driver) (POR:4.46; 95% CI:1.15-14.6; p=0.018). However, there is no seropositivity difference between farmers and non-farmers. Lifestyle choices such as smoking and alcohol consumption were also influential. Smokers had lower odds of seropositivity (POR:0.274; 95% CI:0.0955-0.723; p\u0026lt;0.001), while alcohol consumers had higher odds (POR:3.27; 95% CI:1.19-9.11; p=0.022), though the alcohol consumers were modest. Activities like walking in fields and rice fields were strongly associated with increased odds of seropositivity (POR:7.20; 95% CI:2.27-34.3; p=0.002 and POR:3.85; 95% CI:1.31-12.1; p=0.010, respectively). Conversely, washing clothes in the river was linked with lower odds of seropositivity (POR:0.118; 95% CI:0.0321-0.380; p=0.001). These findings underscore the demographic and lifestyle factors contributing to seropositive status, which could guide targeted public health interventions.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIndia, a hotspot for melioidosis, exhibiting significant isolation of \u003cem\u003eB. pseudomallei\u003c/em\u003e from soil and water (4). This study found an 8.13% seroprevalence among family members of melioidosis patients, highlighting notable exposure. The findings on demographic and lifestyle factors provide valuable insights for informing targeted public health interventions.\u003c/p\u003e\n\u003cp\u003eThe Indirect Hemagglutination Assay (IHA), introduced in 1965, is valued for its simplicity, speed, and effectiveness in detecting antibodies (16,17). However, in melioidosis-endemic regions, IHA\u0026apos;s specificity and sensitivity are poor (18). Our study used a cut-off titer of \u0026ge;1:40 to enhance specificity, aligning with research from Southern India (4). While this increases specificity, it can reduce sensitivity (19). Conversely, a lower cut-off, such as \u0026ge;1:10, increases sensitivity, as seen in a Puducherry study where seropositivity rose to 25.6% (20). Participants with a positive IHA titer (\u0026ge;1:40) were predominantly female and older, aligning with prior research suggesting age and gender influence susceptibility to infectious diseases (4). The study found an overall seroprevalence of 8.13% (n=20), with 56.9% showing no seropositivity. \u0026nbsp;Antibody titers of 1:20 were found in 23.9% (n=59) of participants, while 10.5% (n=26) had titers of 1:10. These results are consistent with previous findings from Southern India, where a seroprevalence rate of 29% was reported using a titer threshold of 1:20 (4), and from Puducherry, where seropositivity was found in 19.8% of participants using a titer of \u0026ge;1:20 (20). Comparisons to studies from other endemic regions vary depending on the antibody titer threshold. For instance, in Thailand, seroprevalence ranged from 6.4% to 31.8%, depending on the titer cutoff used (21). Similarly, Vietnam reported rates between 6.4% and 31.8% (23), and Bangladesh reported a seroprevalence of 28.9% (24). However, in Australia, studies have typically used higher titer cutoffs, such as 1:40 or above, explaining the lower observed rates of around 3% (22). The difference in thresholds complicates direct comparison, but the broader exposure context in regions with endemic melioidosis remains relevant.\u003c/p\u003e\n\u003cp\u003eIn Southern India, farmers face higher melioidosis risks due to frequent contact with the bacterium. The study found higher seropositivity among farmers, consistent with findings from Puducherry, Bangladesh, and Thailand (20,24), where farmers are 4.6 times more likely to test positive (19). However, one Bangladesh study reported no significant difference between farmers and non-farmers (24). These findings highlight farmers\u0026apos; increased vulnerability to melioidosis with activities involving direct contact with soil (walking in fields, rice paddies and gardening) were strongly associated with seropositivity. Vandana et al. found that gardening and river water sources increase exposure to \u003cem\u003eB. pseudomallei\u003c/em\u003e (4). However, our study suggests a lower correlation between washing clothes in rivers and IHA titers, possibly reflecting increased awareness of melioidosis transmission risks among the population. Public health education campaigns and local initiatives in endemic regions may have successfully informed communities about the dangers of contact with contaminated water sources, such as rivers. As a result, behavioural changes, including reducing or avoiding practices like washing clothes in these rivers, may have decreased exposure to the bacterium, leading to lower antibody titers in individuals. These shifts in behaviour highlight the importance of awareness in mitigating risk and controlling potential exposure. In Taiwan, walking barefoot and exposure to flooding increased melioidosis risk (25), whereas a study in Puducherry found no significant correlation between seropositivity and smoking, alcohol, water proximity, gardening, or footwear (20).\u003c/p\u003e\n\u003cp\u003eThe association between age and seropositivity is unclear. Previous research in Southern India found no significant variations among adults (4). However, our current study shows higher seropositivity in those aged 41-50, suggesting recurrent exposure, aligning with findings from Bangladesh (26) and Puducherry (20), which show higher rates in older age groups. In contrast, Thailand shows increasing seropositivity among children with age (27-29), while Australia reports decreasing seroprevalence with age (30).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eGender-specific seropositivity rates vary across studies, with Australia (6) and Bangladesh (26) reporting comparable rates between sexes, while our investigation found higher seropositivity in females. This discrepancy is notable as melioidosis predominantly affects males. Vandana et al. (4) suggested that behavioural patterns and environmental exposures might explain this difference, with females potentially seroconverting without symptoms due to fewer outdoor activities. Ongoing serosurveillance among high-risk individuals, particularly farmers in agricultural regions, is essential. These findings can inform targeted surveillance and environmental control measures and aid public health policy decisions. Targeted public health interventions could include customized educational campaigns to raise awareness about melioidosis and preventive measures, particularly for high-risk groups such as agricultural workers and individuals with frequent exposure to contaminated soil and water. Additionally, improving access to diagnostic and treatment facilities in affected areas and implementing regular screening programs for at-risk populations could help in the early detection and management of the disease. By focusing these interventions on individuals with identified risk factors, public health efforts can more effectively reduce the incidence and impact of melioidosis.\u003c/p\u003e\n\u003cp\u003eThis study\u0026apos;s limitations are excluding healthy children, limiting younger age group seropositivity assessment, and the Indirect Haemagglutination Assay\u0026apos;s (IHA) variable sensitivity and specificity. \u0026nbsp;Future research should build on these findings by utilizing more precise diagnostic methods. Advanced molecular techniques, such as polymerase chain reaction (PCR) for detecting \u003cem\u003eB. pseudomallei\u003c/em\u003e DNA, enzyme-linked immunosorbent assays (ELISA) for improved antibody detection, or whole-genome sequencing (WGS) for highly specific pathogen identification, could offer more accurate diagnoses. These methods would help overcome the limitations of serological tests, such as IHA, in terms of specificity and sensitivity, providing more reliable data for both epidemiological surveillance and patient management in melioidosis-endemic regions.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, this study highlights the impact of demographic and lifestyle factors on melioidosis seroprevalence and symptomatic status among family members of positive cases. Early detection and proactive management are crucial for controlling the disease within affected communities. Identified risk factors, including gender, occupation, and environmental exposures, can guide targeted public health strategies in endemic regions. Further research is needed to explore the mechanisms behind these correlations and develop effective interventions to reduce disease burden and enhance understanding of melioidosis transmission dynamics within households.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval was obtained from the Kasturba Medical College and Kasturba Hospital Ethics Committee (reference number 77/2020) along with the informed consent of all study participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent of publications\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have approved of the manuscript and agree with the submission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data underlying the results are available in the article; no additional source data are required.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors report there are no competing interests to declare.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by the Indian Council of Medical Research (ICMR), New Delhi, India to C.M [Grant number 2020-1381]. Department of Science and Technology also supported this study to S.C [Grant number DST/INSPIRE/03/2018/003582]. The funders had no role in study design, data collection and analysis, preparation of the manuscript, or the decision to publish.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eS.C. designed the study, performed sample and clinical data collection, interpreted the analysis, and wrote the manuscript. V.K.E. provided intellectual input and reviewed the manuscript. C.M. designed the study, assisted with the results, writing and reviewed the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe are grateful to all patients\u0026rsquo; family members who participated in the study and all staff involved in the data collection. We thank Mr Venkat Abhiram Earny for helping with the collection and processing of sheep blood for this study.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eCheng AC, Currie BJ. Melioidosis: epidemiology, pathophysiology, and management. Clin Microbiol Rev 2005; 18:383\u0026ndash;416.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCurrie BJ, Fisher DA, Howard DM, Burrow JN, Lo D, Selva-Nayagam S, et al. Endemic melioidosis in tropical northern Australia: a 10-year prospective study and review of the literature. Clin Infect Dis. 2000; 31:981\u0026ndash;986.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCurrie BJ. Melioidosis: an important cause of pneumonia in residents of and travelers returned from endemic regions. Eur Respir J 2003; 22: 542\u0026ndash;550.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eVandana KE, Mukhopadhyay C, Tellapragada C, Kamath A, Tipre M, Bhat V, et al. Seroprevalence of Burkholderia pseudomallei among Adults in Coastal Areas in Southwestern India. PLoS Negl Trop Dis. 2016; 10(4): e0004610.\u003c/li\u003e\n \u003cli\u003eMukhopadhyay C, Shaw T, Varghese G, Dance D. 2018. Melioidosis in South Asia (India, Nepal, Pakistan, Bhutan and Afghanistan). Trop Med Infect Dis. 2018; 3:51.\u003c/li\u003e\n \u003cli\u003eLazzaroni SM, Barnes JL, Williams NL, Govan BL, Norton RE, LaBrooy JT, et al. Seropositivity to Burkholderia pseudomallei does not reflect the development of cell-mediated immunity. Trans R Soc Trop Med Hyg 2008; 102(S1), S66 \u0026ndash;S70.\u003c/li\u003e\n \u003cli\u003eChaichana P, Jenjaroen K, Amornchai P, Chumseng S, Langla S, Rongkard P, et al. Antibodies in melioidosis: The Role of the Indirect Hemagglutination Assay in Evaluating Patients and Exposed Populations. Am J Trop Med Hyg. 2018; 99(6):1378\u0026ndash;1385.\u003c/li\u003e\n \u003cli\u003eWhite N J. Melioidosis. Lancet. 2003; 361:1715\u0026ndash;1722.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eBrent AJ, Matthews PC, Dance DA, Pitt TL, Handy R. Misdiagnosing melioidosis. Emerg Infect Dis. 2007; 13:349\u0026ndash;351.\u003c/li\u003e\n \u003cli\u003eDance DA, Smith MD, Aucken HM, Pitt TL. Imported melioidosis in England and Wales. Lancet. 1999; 353:208.\u003c/li\u003e\n \u003cli\u003eThurnheer U, Novak A, Michel M, Ruchti C, Jutzi H, Weiss M. Septic melioidosis following a visit to India. Schweiz Med Wochenschr. 1988; 118:558\u0026ndash;564.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eMukhopadhyay C, Chawla K, Krishna S, Nagalakshmi N, Rao SP, Bairy I.Emergence of Burkholderia pseudomallei and pandrug-resistant non fermenters from southern Karnataka, India. Trans R Soc Trop Med Hyg. 2008; 102: S12\u0026ndash;17.\u003c/li\u003e\n \u003cli\u003eVidyalakshmi K, Lipika S, Vishal S, Damodar S, Chakrapani M. Emerging clinico-epidemiological trends in melioidosis: analysis of 95 cases from western coastal India. Int J Infect Dis. 2012; 16:e491\u0026ndash;497.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSharon Peacock, V. Wuthiekanun. Standard operating procedure (SOP) of indirect haemagglutination assay (IHA) for melioidosis. Mahidol-Oxford Tropical Medicine Research Unit (MORU). Faculty of Tropical Medicine, Mahidol University. 2011. \u0026nbsp; Available:http://www.melioidosis.info/download/MICRO_SOP_IHA_ENG_v1%203_8Dec11_SDB.pdf.\u003c/li\u003e\n \u003cli\u003ePeacock SJ, Cheng AC, Currie BJ, Dance DAB. The Use of Positive Serological Tests as Evidence of Exposure to Burkholderia pseudomallei. Am J Trop Med Hyg. 2011; 84:1021\u0026ndash;1022.\u003c/li\u003e\n \u003cli\u003eHarris PNA, Williams NL, Morris JL, Ketheesan N, Norton R E. Evidence of Burkholderia pseudomallei-Specific Immunity in Patient Sera Persistantly Nonreactive by the Indirect Hemagglutination Assay. Clin. Vaccine Immunol. 2011; 18:1288\u0026ndash;1291.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCheng AC, O\u0026rsquo;Brien M, Freeman K, Lum G, Currie BJ. Indirect Hemagglutination Assay In Patients With Melioidosis In Northern Australia. Am J Trop Med Hyg. 2006; 74(2):330\u0026ndash;334.\u003c/li\u003e\n \u003cli\u003eTiyawisutsri R, Peacock SJ, Langa S, Limmathurotsakul D, Cheng AC, Chierakul W, et al. Antibodies from Patients with Melioidosis Recognize Burkholderia mallei but Not Burkholderia thailandensis Antigens in the Indirect Hemagglutination Assay. J Clin Microbiol. 2005; 43:4872\u0026ndash;4874.\u003c/li\u003e\n \u003cli\u003eNorazah A, Rohani MY, Chang PT, Kamel AGM. Indirect Hemagglutination antibodies against Burkholderia pseudomallei in normal blood donors and suspected cases of melioidosis in Malasiya. Southeast Asian J Trop Med Public Health. 1996; 27 (2):263\u0026ndash;266.\u003c/li\u003e\n \u003cli\u003eRaj S, Sistla S, Melepurakkal Sadanandan D, Kadhiravan T, Chinnakali P. Estimation of seroprevalence of melioidosis among adult high-risk groups in Southeastern India by indirect Hemagglutination assay. PLOS Global Public Health. 2022;2(5):e0000431.\u003c/li\u003e\n \u003cli\u003eChaichana P, Jenjaroen K, Amornchai P, Chumseng S, Langla S, Rongkard P, et al. Antibodies in melioidosis: The Role of the Indirect Hemagglutination Assay in Evaluating Patients and Exposed Populations. Am J Trop Med Hyg. 2018; 99(6):1378\u0026ndash;1385.\u003c/li\u003e\n \u003cli\u003eJames GL, Delaney B, Ward L, Freeman K, Mayo M, Currie BJ. Surprisingly Low Seroprevalence of Burkholderia pseudomallei in Exposed Healthy Adults in the Darwin Region of Tropical Australia Where Melioidosis Is Highly Endemic. Clin Vaccine Immunol. 2013; 20:759\u0026ndash;760.\u003c/li\u003e\n \u003cli\u003eVan Phung L, Quynh HT, Yabuuchi E, Dance DA. Pilot study of exposure to Pseudomonas pseudomallei in northern Vietnam. Trans R Soc Trop Med Hyg. 1993; 87:416.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eMaude RR, Maude RJ, Ghose A, Amin MR, Islam MB, Ali M, et al. Seroepidemiological surveillance of Burkholderia pseudomallei in Bangladesh. Trans R Soc Trop Med Hyg. 2012; 106:576\u0026ndash;578.\u003c/li\u003e\n \u003cli\u003eSu HP, Yang HW, Chen YL, Ferng TL, Chou YL, Chung TC, et al. Prevalence of Melioidosis in the Er-Ren River Basin, Taiwan: Implications for Transmission. J Clin Microbiol. 2007; 45: 2599\u0026ndash;2603.\u003c/li\u003e\n \u003cli\u003eJilani MS, Robayet JA, Mohiuddin M, Hasan MR, Ahsan CR, Haq JA. Burkholderia pseudomallei: Its Detection in Soil and Seroprevalence in Bangladesh. PLoS Negl Trop Dis. 2016; 10: e0004301.\u003c/li\u003e\n \u003cli\u003eWuthiekanun V, Chierakul W, Langa S, Chaowagul W, Panpitpat C, Saipan P, et al. Development of Antibodies to Burkholderia pseudomallei During Childhood in Melioidosis-Endemic Northeast Thailand. Am J Trop Med Hyg. 2006; 74:1074\u0026ndash;1075.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCharoenwong P, Lumbiganon P, Puapermpoonsiri S. The Prevalence of the Indirect Hemagglutination Test for Melioidosis in Children in an Endemic Area. Southeast Asian J Trop Med Public Health. 1992;23:698\u0026ndash;701.\u003c/li\u003e\n \u003cli\u003eWuthiekanun V, Pheaktra N, Putchhat H, Sin L, Sen B, Kumar V, et al. Burkholderia pseudomallei Antibodies in Children, Cambodia. Emerg Infect Dis. 2008; 14:301\u0026ndash;303.\u003c/li\u003e\n \u003cli\u003eArmstrong PK, Anstey NM, Kelly PM, Currie BJ, Martins N, Dasari P, et al. Seroprevalence of Burkholderia pseudomallei in East Timorese Refugees: Implications for Healthcare in East Timor. Southeast Asian J Trop Med Public Health. 2005; 36: 1496\u0026ndash;1502.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003e\u003cstrong\u003eTable 1. Clinical demographics among seropositive and seronegative individuals:\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"662\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSeropositive (IHA \u003cu\u003e\u0026gt;\u003c/u\u003e40) = 20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSeronegative (IHA\u0026lt;40) = 226\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eP-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCrude POR (95%CI)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eAge (mean (SD))\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e49.35 (11.31)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e44.56 (12.20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.092\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e1.03 (0.995-1.08)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eAge categories (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e18-30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e1 (5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e27 (11.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e0.037 (0.018-0.076)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e31-40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e6 (30.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e96 (42.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.634\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e1.687 (0.825-3.449)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e41-50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e3 (15.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e25 (11.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.332\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e3.240(1.312-7.993)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u0026gt;50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e5 (25.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e78 (34.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.244\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e3.462(1.073-11.202)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGender\u0026nbsp;\u003c/strong\u003e(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eMale sex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e5 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e145 (64.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e0.186 (0.058-0.500)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eFemale sex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e15 (75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e81 (35.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e5.368 (0.186 - 0.500)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMajor occupational group, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eFarmer\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e12(60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e71(31.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.019\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e3.27 (1.30-8.69)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNon-Farmer\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e8(40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e155 (68.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSkill level job\u0026nbsp;\u003c/strong\u003e(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eProfessionals\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e4 (20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e12 (5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e4.46 (1.15-14.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eSales worker\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e0 (0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e8 (3.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.843\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eProduction worker\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e1 (5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e44 (19.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.193\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e0.23 (0.003-4.26)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eAgricultural worker\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e2 (10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e26 (11.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e0.861 (0.065-5.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eOther work\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e1 (5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e65 (28.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.042\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e0.143 (0.003-2.59)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSmoking, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e9 (45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e169 (74.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e0.274 (0.095-0.723)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e6 (30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e52 (23)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eRefused to answer\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e5 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e5 (2.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAlcohol consumption, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e10 (50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e67 (29.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e3.27 (1.19-9.11)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e5 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e146 (64.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eRefused to answer\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e5 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e13 (5.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWalking in fields, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e15 (75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e59 (26.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e7.20 (2.27-34.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e5 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e167 (73.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWalking in the rice field, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e11 (55)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e57 (25.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.010\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e3.85 (1.31-12.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e9 (45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e169 (74.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGardening, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e8 (40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e43 (19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.054\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e2.72 (0.976-7.58)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e12 (60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e183 (80.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWash clothes in the river, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e6 (30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e159 (70.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e0.118 (0.032-0.380)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e14 (70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e67 (29.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWear footwear, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eAlways\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e14 (70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e189 (83.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.218\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e1.09 (0.236-4.92)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eSometimes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e6 (30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e37 (16.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.218\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e2.02 (0.398-9.76)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiabetes, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e15 (75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e168 (74)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e0.843\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e1.15 (0.141-10.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e4 (20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e39 (17.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eDon\u0026rsquo;t know\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e1 (5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e19 (8.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOther Comorbidities, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e6 (30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e54 (23.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e1.36 (0.310-6.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 25.7186%;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.121%;\"\u003e\n \u003cp\u003e7 (35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 18.4569%;\"\u003e\n \u003cp\u003e172 (76.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 12.8593%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.8442%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[{"identity":"4669d804-8f7e-4608-815a-5a007216f51a","identifier":"10.13039/501100001411","name":"Indian Council of Medical Research","awardNumber":"Grant number 2020-1381","order_by":0},{"identity":"ed94b995-4096-47d4-a93d-3c517623cd45","identifier":"10.13039/501100001409","name":"Department of Science and Technology, Ministry of Science and Technology, India","awardNumber":"Grant number DST/INSPIRE/03/2018/003582","order_by":1}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India","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":"Melioidosis, Burkholderia pseudomallei, Indirect Hemagglutination Assay, family members, India","lastPublishedDoi":"10.21203/rs.3.rs-6988004/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6988004/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e Melioidosis, caused by \u003cem\u003eBurkholderia pseudomallei\u003c/em\u003e, is a significant public health concern in tropical regions. This study aimed to identify predictors of high IHA titers among family members of culture-proven melioidosis patients, providing valuable insights into its epidemiology.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e A cross-sectional study was conducted at Kasturba Hospital, Manipal, India from June 2020 to December 2022; enrolled adult family members of melioidosis patients without recent signs of infection or antibiotic exposure. Blood samples were tested for anti-\u003cem\u003eB. pseudomallei\u003c/em\u003eantibodies using the indirect hemagglutination (IHA) assay. Socio-demographic and lifestyle data were collected via detailed questionnaires. Logistic regression identified predictors of seropositive individuals (IHA titer \u003cu\u003e\u0026gt;\u003c/u\u003e40), with results presented as prevalence odds ratios (POR) and 95% confidence intervals (CI).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Among the 246 participants (mean age 46.1 years), the seroprevalence rate was 8.13%. Significant predictors of high IHA titers included older age (POR: 1.03 per year; CI: 0.995-1.08; p=0.092), female gender (POR: 0.186; CI: 0.0588-0.500; p=0.001), occupation as a farmer (POR: 3.27; CI: 1.30-8.69; p=0.019), and activities like walking in fields (POR: 7.20; CI: 2.27-34.3; p = 0.002) or rice fields (POR: 3.85; CI: 1.31-12.1; p=0.010). Conversely, smoking (POR: 0.274; CI: 0.0955-0.723; p\u0026lt;0.001) and washing clothes in the river (POR: 0.118; CI: 0.0321-0.380; p=0.001) showed a decreased likelihood of high IHA titers.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e These findings highlight key demographic and lifestyle factors associated with high IHA titers among family members of melioidosis patients, guiding targeted public health interventions to reduce \u003cem\u003eB. pseudomallei\u003c/em\u003e exposure.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registered: \u003c/strong\u003eThis study has been registered in Clinical Trial Registry India; CTRI registration number: CTRI/2020/06/025663; CTRI registration date: 02/06/2020.\u003c/p\u003e","manuscriptTitle":"Estimation of Seropositivity to Burkholderia pseudomallei Among Family Members of Melioidosis Patients by Indirect Hemagglutination Assay","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-01 10:49:01","doi":"10.21203/rs.3.rs-6988004/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":"9d726205-c9a8-4cfb-b459-1bd4495cbc31","owner":[],"postedDate":"July 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":50670946,"name":"Infectious Diseases"},{"id":50670947,"name":"Epidemiology"}],"tags":[],"updatedAt":"2025-07-01T10:49:02+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-01 10:49:01","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6988004","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6988004","identity":"rs-6988004","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}