Public health aspects of opisthorchiasis in Thailand.

Opisthorchiasis is one of the diseases of public health importance in Thailand. It has been estimated that approximately 7 million of the population harbour this liver fluke. Although the mortality rate is not high, the morbidity causes increased loss of man power (work days lost) and economic problems to the people. The infection is common among the rural population of Northeast Thailand, which has increased from 3.5 million in 1965 to 5.4 million in 1981. This high prevalence is due to the population explosion and adverse effects of development of reservoirs and large scale irrigation systems in the area, thereby increasing the fisheries of intermediate hosts. The increased prevalence is also attributed to lack of proper sanitation facilities and people's customary habit of eating raw fish. In spite of control measures to reduce the prevalence rate through improved sanitation and health education, success could not be achieved. It is, however, hoped that through extended primary health care, intensified health education and mass treatment with the drug of choice, the campaign to control opisthorchiasis will finally meet with success.