Surveillance of schistosomiasis in five provinces of China which have reached the national criteria for elimination of the disease.

Surveillance of schistosomiasis consists mainly of surveys carried out in formerly endemic areas to observe infection and re-infection of resident and mobile human populations, and domestic animals (e.g. bovines) plus snail monitoring. Here, we focus on the schistosomiasis situation in the five Chinese provinces which have reached the national criteria for elimination of the disease, i.e. Fujian, Guangdong, Guangxi, Shanghai and Zhejiang. With the exception of three newly infected persons in Guangdong province, detected in 1992, repeated surveys in these provinces have not detected any new locally infected case in either humans or bovines. When the newly infected persons were discovered in Guangdong, residual snail habitats including Schistosoma japonicum-infected snails were found in the neighbourhood. These were destroyed and the infected persons treated before further spread could take place. The surveillance system in place has thus been successful in consolidating the results of the control effort. We conclude that rigorous surveillance for and control of schistosomiasis is the way to prevent resurgence of infection and disease in areas which have reached the national criteria for elimination or transmission interruption.