Clinical Report: Prevalence of Burkholderia pseudomallei Antibodies in Travelers
Overview
This cross-sectional study assessed Burkholderia pseudomallei antibodies in 370 international travelers to Southeast Asia. Forty-nine travelers (13.2%) met a study threshold for seropositivity. All were clinically healthy when tested, so the results did not establish that they had clinical melioidosis.
Background
Melioidosis is caused by B. pseudomallei, a bacterium found in soil and water. Illness can range from subclinical infection to life-threatening septicemia and may be misdiagnosed. The extent of serological evidence of exposure among international travelers had not been systematically assessed.
Objective
To estimate B. pseudomallei antibody seroprevalence among travelers to Southeast Asia and identify factors associated with seropositivity.
Approach
Researchers enrolled 370 adults from nonendemic regions who had spent at least one month in Southeast Asia. At a hospital in Bangkok, participants completed travel and medical-history questionnaires, and their blood samples were tested for antibodies to Hcp1 and O-polysaccharide. Researchers applied separate thresholds for probable melioidosis and probable environmental exposure.
Data Highlights
Forty-nine of 370 travelers (13.2%) were seropositive.
Twenty-five (6.8%) met the antibody threshold for probable melioidosis; another 24 (6.5%) met the threshold for probable environmental exposure.
A separate study cited by the authors found detectable antibodies in 13 of 34 U.S. Marines (approximately 38%) after an exercise in Thailand. That was not a result of the present study.
Key Findings
Female sex, North American origin, and at least one underlying medical condition were independently associated with seropositivity.
All seropositive participants were clinically healthy at the time of testing.
The antibody classifications did not confirm clinical melioidosis or establish when exposure occurred.
Interpretation
Approximately one in eight travelers met a study threshold for seropositivity. The findings provide serological evidence of possible exposure in this cohort, but a positive antibody result alone cannot establish clinical infection.
Clinical Implications
The authors support considering melioidosis in the differential diagnosis of febrile returning travelers. The study does not establish routine antibody screening for travelers who feel well.
Limitations
This single-center, cross-sectional study cannot determine whether antibodies arose during the current trip or an earlier exposure. Travel exposures were self-reported, and the O-polysaccharide assay may cross-react with other environmental Burkholderia species, potentially inflating the estimated B. pseudomallei-specific seroprevalence.
Conclusion
B. pseudomallei antibody seropositivity was detected in 13.2% of the travelers studied. Further research is needed to determine the clinical significance of seropositivity in travelers who feel well and the role of post-travel antibody screening.
Related Resources & Content
Ali QM, Zschebek G, Cagape CMS, et al. “Seroprevalence of Burkholderia pseudomallei among international travelers.” International Journal of Infectious Diseases. 2026;172:109085.
Gassiep I, Armstrong M, Norton R. “Human melioidosis.” Clinical Microbiology Reviews. 2020;33:e00006-19.
Norman FF, Chen LH. “Travel-associated melioidosis: a narrative review.” Journal of Travel Medicine. 2023;30:taad039.
Kronmann KC, Truett AA, Hale BR, Crum-Cianflone NF. “Melioidosis after brief exposure: a serologic survey in US Marines.” American Journal of Tropical Medicine and Hygiene. 2009;80:182–184.
Pumpuang A, Dunachie SJ, Phokrai P, et al. “Comparison of O-polysaccharide and hemolysin co-regulated protein as target antigens for serodiagnosis of melioidosis.” PLOS Neglected Tropical Diseases. 2017;11:e0005499.
Chen C, Fang J, Li X, et al. “Diagnostic accuracy of non-culture methods for the diagnosis of melioidosis: a systematic review and meta-analysis.” BMC Infectious Diseases. 2025;25:851.
