The control of clonorchiasis in Guangdong province, southern China.

Oriental liver fluke disease (clonorchiasis), caused by Clonorchis sinensis, is endemic in 81 counties in Guangdong province, China. This study was conducted following increasing lack of clonorchiasis awareness and increased consumption of raw freshwater fish and raw fish porridge at home and restaurants, which has been attributed to improved living standards in China, and is considered to have led to a higher C. sinensis infection rate in the country. A total of 61,517 individuals were investigated from 123 sites during a provincial survey in 1988, with average C. sinensis infection rate of 1.82% that increased to 4.08% (335/8217) in 1997. Higher infection rate was observed in adult men than women, with heavy infection rate in fishermen and businessmen because they have access and means to get raw fishes for consumption. Thus, clonorchiasis has become a serious public health problem in Guangdong province. Efforts targeting clonorchiasis prevention and control in Guangdong province started in the 1990s. These included carrying out large-scale surveys and chemotherapy in epidemic regions, research on promotion of environmental sanitation and methods for freshwater aquaculture. Establishment and promotion of clonorchiosis demonstration plots for comprehensive control measures, as well as the development of clonorchiasis-prevention community-out-patient clinics were initiated and their effectiveness was evaluated. However, there seem to be no obvious decline in the prevalence of C. sinensis with 4.90% (608/12,401) in 2015, at Guangdong province due to the people's habit of eating raw fishes in endemic areas. This has led to increasing calls to improve environmental sanitation in the aquaculture industry. It is, however, believed that control efforts on clonorchiosis in the province are at an early stage and require strengthening through the cooperation of different departments to work out effective strategies for sustainable field application of control mechanisms.