Seroprevalence of melioidosis and its associated risk factors -A population-based study in Odisha, Eastern India

Melioidosis, caused by Burkholderia pseudomallei, is an emerging disease in Odisha, a state in eastern coastal India. Difficult to diagnose, the disease is likely to be severely underreported. Seroprevalence studies in the general population are deemed necessary for an estimate of melioidosis endemicity and to explore the associated risk factors. A population-based cross-sectional seroprevalence study was conducted using Indirect Hemagglutination Assay (IHA) among 1920 participants aged 5-60 years residing in six out of thirty districts of Odisha from August to December 2023. Seropositivity was defined as an IHA titer ≥ 1:20. The risk factors associated with seropositivity were determined. Out of 1920 individuals, 1215 (63.3 %) were females and 1680 (87.5 %) were rural residents. 410 out of 1920 individuals had IHA titer ≥ 1:20, contributing to an overall prevalence of 20.9 % [95 % CI: 19.0 % - 22.7 %]. Seropositivity was highest among those aged 21 to 30 years [23.2 % (95 % CI: 19.2 % - 27.4 %)], and in females [21.7 % (95 % CI: 19.4 % - 24.1 %)]. The odds of seropositivity were 1.64 [95 % CI: 1.097 - 2.436, p= 0.016] times higher among rural residents than urban residents with people engaged in cultivation, daily activities involving soil, and water bodies having higher odds of seropositivity (Crude Odds Ratios, 1.22, 1.11 and 1.17 respectively).The present study, covering a single post-monsoon season in Odisha, has yielded a 20.9 % melioidosis seropositivity, matching previous Indian studies with B. pseudomallei seropositivity rates ranging from 20-29 %. The study indicates towards widespread environmental presence of B. pseudomallei, more so in rural areas and thus risk of clinical melioidosis. Adoption of public health interventions as well creation of awareness is of paramount importance in such a scenario.