Epidemiological studies on cystic echinococcosis in China--a review.

In the four decades from 1951 to 1990, the six provinces or autonomous regions (Xinjiang, Gansu, Qinghai, Ningxia, Xizang and Nei Monggol) reported a total of 26,065 surgical cases of hydatid disease, most of which were reported in the recent decade. About one third of the patients was children and adolescents under 15 years old. So far, cystic hydatid infections of local origin have been confirmed in 22 provinces, autonomous regions and municipalities in the whole nation. Findings of X-ray examination and real-time B-mode ultrasonography in agricultural and pastoral areas of Xinjiang, Gansu, Qinghai, Ningxia and Xizang showed that the morbidity rate of hydatidosis in human population varied between 0.5% and 4.5%. The main animal intermediate host in all these regions is sheep, the morbidity of which varied between 3.3% and 90%. The infection rate of adult Echinococcus granulosus in dogs varied between 7% and 71%. The high-risk period for humans contracting hydatid disease is the pre-school age. Direct contact of children with dogs and ingestion of water, vegetables and foods contaminated by worm eggs are the chief mode of transmission for human hydatidosis. The common practices of home slaughter and of feeding dogs on offal containing hydatid cysts facilitate the life cycle of the parasite. On the basis of hydatid control efforts for several years, the Ministry of Public Health promulgated officially the "1992-1995 National Programme for Hydatid Disease Control" in April, 1992, and pilot studies in which the control of hydatidosis is composed of extensive health education, sanitation of slaughtering and management and deworming of dogs are being established. Cystic echinococcosis has wide distribution in China and is a major public health problem in hyperendemic areas, poses a great threat against people's health and influences the development of livestock husbandry. This problem has received great attention from the medical and veterinary departments. In the recent decade great efforts have been made in the epidemiology, parasitology and clinical treatment of echinococcosis, resulting in a better understanding of the disease and procedures effective in bringing about control of the disease.