Abstract:

【Abstract】 Objective  To analyze the distribution characteristics, infection degree and endemic patterns of Oncomelania hupensis in Tongling area from 2007 to 2013 in order to provide evidence for planning the guidelines and strategies with control schistosomiasis to the local conditions.  Methods  Retrospective analysis was performed on the data collected from the snail habitat records and work reports on schistosomiasis prevention and control during 2007 and 2013. Data analysis was associated with the change trend of areas of snail presence, infected areas with the Oncomelania hupensis and its infection rate in different years, as well as comparison of the data, including the endemic patterns and infection degree between years. Results  From 2007 to 2013, solid area of snail appearance and snail infected area were decreased by 332.28hm2 and 29.68hm2, with decrease rate of 10.69% and 100%, respectively. Currently, the real area of snail occurrence at marshlands of the river and lake were 39.64% to 51.93% out of the total infected areas in history, and current area for snail appearance was 2.95% to 3.51% out of the hilly areas historically infected. Snail infection rate was reduced from 0.148% to 0% , and the reduction rate was 100% (χ2=27.82, P<0.01). In 7 years, the areas for newly-discovered snail habitats in marshlands of river and lake as well as hilly areas were 0hm2 and 6hm2 (accounted for 100%). Constituent ratio of the actual areas for snail occurrence at marshlands of river and lake and hilly areas were 97.66%~97.92% and 2.08%~2.34%, respectively. Conclusion  Areas for the snail appearance and areas infected with Oncomelania hupensis tend to overall decreased in Tongling. The coming control considerations for snail prevalence shall be focused on comprehensive management. Importantly, these measures should target at the distribution nature of Oncomelania hupensis at the marshlands of rivers and lakes as well as hilly areas in order to gradually exterminate the snail habitats and effectively contain the prevalence of schistosomiasis.

Key words: Schistosomiasis, Oncomelania snail distribution, Tongling city