Anti-Ascaris IgG Seroprevalence and ELISA Performance Among Adults in Three Regions of Kazakhstan

Regional surveys can help characterize adult exposure to Ascaris and assess the interpretation of different laboratory markers. This cross-sectional study examined 2001 volunteers from the Akmola, Pavlodar, and North Kazakhstan Regions during 2025–2026. Questionnaire data were collected, and paired serum and stool specimens were tested using the MVA GROUP IgG ELISA and Kato–Katz method. Associations with seropositivity were evaluated using multivariable logistic regression, and 300 selected sera were compared with the DRG Ascaris IgG ELISA. Overall seroprevalence was 28.0% (95% CI: 26.1–30.0%), with regional differences remaining after adjustment for age, sex, residence, and sampling year. Kato–Katz positivity was 8.4%, without a significant regional difference. ELISA sensitivity and specificity relative to Kato–Katz were 85.2% and 77.2%, respectively. Agreement with DRG was 95.0% (κ = 0.900). These findings support further regional assessment of adult exposure. Agreement between ELISAs supports consistent antibody classification in the selected panel, while discordance with Kato–Katz requires separate interpretation of antibody detection and intestinal egg shedding.