Elimination of schistosomiasis japonica from formerly endemic areas in mountainous regions of southern China using a praziquantel regimen.

Schistosomiasis japonica is a major public health problem in China. Domestic animals play a major role in the transmission of Schistosoma japonicum to humans. To better understand the epidemiology of schistosomiasis japonica in domestic animals in the mountainous areas of China, we performed a 5-year longitudinal study of schistosomiasis in cattle and horses in Yunnan Province from 2009 to 2013. We also performed a concurrent drug-based intervention study in three settlement groups in Yunnan Province aimed at developing an effective means of controlling transmission in this region. The prevalence of infection in cattle fluctuated between 1.67% and 3.05% from 2009 to 2011, and monthly treatments of schistosome-positive animals reduced the prevalence to 0% (P<0.05) from 2012 to 2013. Prior to the intervention, we found that schistosomiasis was prevalent from May to October, with the highest prevalence observed in June (10.00%). We surveyed for environmental schistosome contamination, and 94.29% of the miracidia found were from cattle. Our study showed that it is possible to eliminate schistosomiasis in domestic animals in the mountainous regions of China by monthly treating cattle and horses from schistosome-positive households from May to October.

[Longitudinal observation of epidemic dynamics of schistosomiasis in bovine in two mountainous endemic regions].

OBJECTIVE: To understand the endemic situation dynamics of schistosomiasis in domestic animals (mainly bovine) in mountainous endemic regions, so as to provide the reference for evaluating the control effect and improving control strategy. METHODS: Two representative pilots (Renmei and Dacang) in mountainous schistosomiasis endemic regions were selected for survey. The schistosome infection status of bovine was investigated by the miracidium hatching method, the pasture of bovine were investigated by home visiting, and the distributions of wild feces and Oncomelania snails, and the snail schistosome infection status were also investigated in April and September every year. RESULTS: The schistosome infection rates of bovine reduced by 98.4% and 93.8% in two pilots in 2007 compared with those in 1993, and the infection intensities also showed a decline trend. The infection rate of wild faces was 0 in Renmei pilot since 1995, while in Dacang pilot, the infection rate of wild feces fluctuated in 2007, and the intensities of living snails and infected snails showed a declined trend. CONCLUSIONS: Due to the special natural environment of mountainous endemic regions, there is a dot-like or band-like distribution of endemic areas. The strengthening of schistosomiasis examination and chemotherapy will rapidly reduce endemic situation. However, to completely interrupt the transmission of schistosomiasis, we should emphasize environmental modification and domestic animal management.