Development of a Model for Opisthorchis viverrini Screening Using the OV-RDT (OV-Rapid Diagnosis Test) in Health Region 7

Abstract

Opisthorchiasis, a liver fluke infection, remains a major public health challenge in northeastern Thailand. Conventional screening using the Modified Kato-Katz stool examination technique is limited by low sensitivity, time constraints, and logistical issues in sample collection especially as infection intensities have declined in recent years. These limitations contribute to false-negative results, underdiagnosis, and ineffective disease control. This action research aimed to develop and evaluate a screening model for opisthorchiasis using a rapid urine diagnostic test (OV-rapid diagnosis test, OV-RDT) as an alternative to stool examination. The study was conducted in three phases: 1) Situation analysis: Identification of local context, problems, and barriers; 2) Model development: Implementation of a four-step PAOR cycle plan, act, observe, and reflect to develop and refine the screening model; and 3) Evaluation: Outcome assessment and model validation. The program was conducted across 57 districts in health region 7, targeting 65,095 individuals aged 15 years and above with risk behaviors, from June 2022 to April 2023. Data collection methods included structured questionnaires, interviews, field observation, and a mobile application for testing result documentation. Descriptive statistics and qualitative content analysis were used for data analysis. The intervention led to the development of a context-specific, community-based screening model, including training, field deployment of the OV-RDT, data quality monitoring, and participatory feedback sessions. Urine-based screening results revealed an overall opisthorchiasis prevalence of 35.97% across Health Region 7. The highest prevalence was observed in Maha Sarakham province (48.24%), with infection rates exceeding 50% in 8 districts. In Maha Sarakham 5 districts, in Kalasin 2 districts and in Roi Et 1 district. Conclusion, the OV-RDT-based screening model, developed through the PAOR process, demonstrated effectiveness and suitability for local implementation when compared to conventional stool examination. The model received positive feedback from all stakeholder levels and shows strong potential for expansion into other high-risk areas. This supports Thailand’s national strategy for sustainably reducing human opisthorchiasis and cholangiocarcinoma-related mortality.