Ecohealth research helps prevent liver cancer in Southeast Asia
Thailand has the highest rates of the deadly liver cancer, cholangiocarinoma, in the world. One of the causes of this cancer is the liver fluke parasite, Opisthorchis viverrini. In parts of northeast Thailand, nearly 85% of the population is infected with liver flukes. To address this major public health concern, IDRC-supported researchers developed an intervention strategy that helped cut the rates of liver cancer in the region in half.
Food preferences spread a deadly parasite
The Southeast Asian liver fluke parasite is endemic in the Lawa Lake region in Khon Kaen Province, in northeast Thailand. It is transmitted to humans and animals when they consume raw or undercooked fish. The parasite’s eggs are then passed back into the environment when contaminated feces enter local water sources.
Previous efforts to control the parasite were partly successful elsewhere in the country, but had failed to reduce infection rates in the Lawa Lake region, where consuming raw fish is a local preference. Using an ecohealth approach, the research team investigated how social and ecological systems contribute to the parasite’s spread.
The initial phase of the research project looked at 11 villages in the Lawa Lake region, with a total population of 5,600 people. Researchers found that 40% of local villagers ate raw or undercooked fish at least once a month, putting them at high risk of infection.
Education improves community health
The researchers identified four villages for the intervention phase of the project. With the help of medical practitioners, community health workers, village leaders, educators, and government officials, the research team led two targeted interventions.
To slow the transmission of the liver fluke parasite, the Thai Ministry of Public Health led a campaign to treat infected individuals and animals. Alongside these efforts, the Lawa Village Community Hospital provided training to village health volunteers about the liver fluke, how it causes liver cancer, and what can be done to prevent infection. Village health volunteers carried out an intensive public health campaign, using local folk music and community gatherings to raise awareness about the importance of good sanitation and the risks of eating raw fish.
This approach has successfully reduced parasitic infection rates among villagers of Lawa Lake by 50%.
Creating long-term solutions
The project’s multi-pronged approach has also been effective in reducing the number of liver fluke parasite eggs in Lawa Lake. This, in turn, has reduced the number of fish carrying the parasite. Because the fish in the lake generally have a life span of two to three years, rates of parasitic infection in the participating villages have dropped quickly. This reduced rates of parasitic infection in the fish in Lawa Lake from 70% to less than 1%. Known as the "Lawa Model," this approach to controlling the liver fluke parasite has gained national and international recognition and is now being applied in other parts of Thailand and neighbouring countries of the Mekong region.
This research is supported through the Ecohealth Emerging Disease Research Initiative (Eco EID) in Southeast Asia. ECO EID is funded by Global Affairs Canada through the Global Health Research Initiative, the Australian Department of Foreign Affairs and Trade, and IDRC.