Surveillance and risk assessment system of schistosomiasis in Jiangsu Prov-ince II Surveillance pattern and effect of Oncomelania hupensis snail status in Dongtai City,Jiangsu Province / 中国血吸虫病防治杂志

ABSTRACT

Objective To explore the method of Oncomelania hupensis snail surveillance in transmission?interrupted re?gions of schistosomiasis,so as to provide a new pattern for the surveillance of snail status in the transmission?interrupted areas. Methods In Dongtai County,north of Jiangsu Province where the transmission of schistosomiasis was interrupted,the surveil?lance of snail status was performed by means of the village?level general survey,village?level sampling survey,snail survey in key settings of township and county,and snail reporting by residents. In addition,quality?control snail sites were set up for quali?ty control. The effectiveness and cost of the four methods of snail surveillance was compared. Results A total of 163 079 set?tings and 22 785.62 hm2 were surveyed in Dongtai County from 2008 to 2013,and 89 residual snail breeding sites were found, with a snail area of 1.48 hm2. The patterns of village?level general survey,village?level sampling survey,and snail survey in key settings of township and county were employed for investigation of 94 550,45 033 and 23 496 settings,consisting of 57.98%, 27.61%and 14.41%of total settings,and 2,0 and 6 settings were found with snails,with 0.021/thousand,0,and 0.255/thou?sand detection rates of settings with snail breading sites,respectively. The pattern of snail survey in key settings of township and county was more effective than that of village?level survey to detect snail breeding sites(χ2 =19.158,P=0). The recovery rate of quality?control snail breeding sites was 52.56%,38.27%and 73.62%for the three patterns of snail survey,respectively,and the pattern of snail survey in key settings of township and county showed a higher quality for snail survey than that of village?lev?el survey(χ2 =111.597 and 85.991,both P=0). During the period from 2008 to 2013,289 person?times reported 279 sus?pected snail habitats and 1 501 living snails,and no Oncomelania snails were found. During the 6?year period,there were 1617.5,964.7 and 527.7 thousand RMB invested for village?level general survey,village?level sampling survey,and snail sur?vey in key settings of township and county,and the cost of snail survey per hm2 was 129.88,133.6 and 162.57 RMB/hm2,re?spectively. The cost of village?level general survey and snail survey in key settings of township and county to detect a snail?breed?ing site was 808 800 and 88 000 RMB,respectively(t=12.850,P=0.000),and the cost of snail survey in key settings of town?ship and county was 10.88%of that of village?level general survey. Conclusion The snail survey in key settings of township and county is a highly effective and high?quality method for snail surveillance,which may serve as a prior way for the surveil?lance of snail status in the transmission?interrupted areas of schistosomiasis.