Geographic information system of Opisthorchis viverrini in northeast Thailand

Background: Opisthorchiasis caused by Opisthorchis viverrini remains a major public health problem in many parts of Southeast Asia including Thailand, Lao PDR, Vietnam, and Cambodia. The epicenter of this disease is located in northeast Thailand, where high a prevalence of opisthorchiasis coexists with a high incidence of cholangiocarcinoma (CHCA), a major primary carcinoma of the liver with a very poor prognosis.

Objective: Determine the surveillance characteristics of O. viverrini infections in northeast Thailand.

Methods: Four thousand one hundred eighteen stool samples from 19 provinces were used in this study. All age groups were included, from below four years to more than 60 years. The geographic information system (GIS) was deployed to overlay the prevalence of disease on urban and agricultural areas as well as manmade land uses.

Results: Results showed a rate of Opisthorchiasis of 20.39% (840/4,118). Farmland and forests (loam soil) were highly associated with infection.

Conclusion: The rate of Opisthorchiasis is high in farmland and forests and lower in residential areas. Mass treatment targeted at high-risk areas may be a cost-effective control strategy and warrants further study.