[2026-06-22] Prevalence and Associated Factors of Opisthorchis viverrini Infection in Nakhon Phanom, Thailand

Background: Opisthorchis viverrini infection remains a major public health problem in northeastern Thailand, particularly in communities near freshwater ecosystems with persistent raw fish consumption. Conventional stool-based diagnostics have limited sensitivity, whereas the O. viverrini-rapid diagnostic test (OV-RDT) improves infection detection. Objectives: To determine the prevalence of O. viverrini infection and identify factors influencing infection among residents of Nakhon Phanom, Thailand. Methods: This retrospective cross-sectional analytical study analyzed routine screening data obtained from the Nakhon Phanom Provincial Public Health Office, including 5093 individuals aged ≥ 15 years who were screened for O. viverrini infection using OV-RDT during 2023-2024. Prevalence, and associated factors were assessed using multivariable logistic regression. Results: The overall prevalence of O. viverrini infection was 52.5%. The prevalence decreased from 63.0% in 2023 to 35.5% in 2024. Significant factors associated with infection included age 35-59 years (adjusted odds ratios [aOR], 1.15; 95% CI, 1.00-1.33), employment in the agricultural sector (aOR, 1.23; 95% CI, 1.01-1.50), consumption of raw or undercooked freshwater fish (aOR, 2.00; 95% CI, 1.64-2.43), and spatial factors, with residents of Wang Yang district exhibiting the highest risk of infection (aOR, 61.05; 95% CI, 37.38-99.73). The final model explained 23.5% of the variance (pseudo R2 = 0.235). Conclusions:O. viverrini infection remains highly prevalent in Nakhon Phanom, Thailand and is driven by individual, behavioral, and spatial factors, supporting the need for targeted, area-based control and prevention strategies.