The Lawa model: A sustainable, integrated opisthorchiasis control program using the EcoHealth approach in the Lawa Lake region of Thailand

Abstract

Opisthorchiasis caused by the carcinogenic liver fluke Opisthorchis viverrini is a major foodborne parasitic zoonotic disease in Thailand and neighboring Mekong countries. The infection is associated with several hepatobiliary diseases including cholangiocarcinoma (CCA). The rates of CCA in regions where the parasite is endemic are unprecedented. Extensive research on various aspects of opisthorchiasis has been conducted in recent decades. However, the current status of O. viverrini infection in the country is approaching 85% prevalence in certain endemic areas even after more than 30years of control programs in Thailand. The complex life cycle of the fluke, which involves several hosts/environments, makes it difficult to control by conventional methods. Therefore, a new control strategy using the EcoHealth/One Health approach named the "Lawa model" was introduced into the liver fluke endemic Lawa Lake region in Khon Kaen Province. This program has been underway for over ten years. The program includes treatment with anthelmintic drugs, novel intensive health education methods both in the communities and in schools, ecosystem monitoring and active community participation. We developed the "Liver fluke-free school program" as a part of the Lawa model with successful results. All key stakeholders were empowered to obtain competency in their control activities for the sustainability of the program in the community. Nowadays, the infection rate in the 12 villages surrounding the lake has declined to less than 10% from an average of 60% at the start. The Cyprinid fish species now show less than 1% prevalence of infection compared with a maximum of 70% during the baseline survey. No infected Bithynia snails in the lake were found during recent field studies. Of the lessons learned from the Lawa model, the importance of community participation is one practical and essential component. The key to the success of the project is multi-stakeholder participation with the active local Health Promoting Hospitals and the village health volunteers. The idea of the Lawa model is on the national agenda against liver fluke infection and CCA and is being scaled up to work in larger areas in Thailand. Internationally, the "Lawa model" is one of two programs that are showcased as successful control programs for helminths by the WHO Neglected Zoonotic Diseases (NZD4). Several media outlets have broadcast news reports about the program.

Keywords: EcoHealth/One Health; Integrated control; Lawa Lake; Lawa model; Liver fluke; Opisthorchiasis; Thailand.