Abstract
OBJECTIVES: Dengue (DENV), Chikungunya (CHIKV), and West Nile (WNV) viruses are among the major mosquito-borne arboviral threats in East Africa. This study assessed seroprevalence and risk factors for DENV, CHIKV, and WNV among residents of Mutukula and Namanga cross borders in Tanzania. METHODS: Blood samples were collected from 450 participants and tested using an enzyme-linked immunosorbent assay for anti-viral immunoglobulin G and M (IgG and IgM) antibodies. Descriptive and multivariate logistic regression analyzed risk factors. RESULTS: Overall seroprevalence was 12.4% for DENV, 10.7% for CHIKV, and 10.2% for WNV. Namanga had higher IgM seroprevalences (DENV: 9.7%, CHIKV: 6.9%, and WNV: 6.3%) than Mutukula (DENV: 5.6%, CHIKV: 5.3%, WNV: 5. 9%). IgG seropositivity for CHIKV was linked to a history of travel abroad (adjusted odds ratio [AOR] 7.3, 95% confidence interval [CI] 1.01-54.6), mosquito exposure (AOR 2.8, 95% CI 1.01-7.7), and being female (AOR 6.1, 95% CI 1.3-28). IgM seropositivity was influenced by education, with secondary levels reducing risk (AOR 0.11, 95% CI 0.02-0.64 for DENV; AOR 0.06, 95% CI 0.1-0.6 for CHIKV). CONCLUSION: This study provides the first evidence of WNV exposure in Tanzania and specific cross-border seroprevalences for DENV and CHIKV transmission. To mitigate the risks, Integrated vector control and enhanced surveillance are highly recommended.