[Efficacy of the Sentinel Mouse Method in Monitoring Schistosoma japonicum Infection in Key #br# Water Areas of Hanchuan City].

Objective: To understand the water infectivity of schistosomes in key water areas of Hanchuan City, and explore the use of sentinel mice in surveillance and forecast of schistosomiasis. Methods: Surveillance and forecast sites were set up in North Han River, Diaocha Lake, and Miaowu Ditch in 2014. Sentinel mice （male Kunming mice, n=20 in each site） were placed there within the first ten-day period of June and September, respectively. Field detections lasted 4 h each, for a total of 2 days. The loss and death rates of mice were recorded. Humans and livestocks with activities in these sites were also examined for schistosome infection. The sentinel mice recovered were raised in laboratory for 35 days, dissected, and examined for liver granulomas and adult worm counting. The distribution of sites with positive detections and their infection status were analyzed. Emergency measures were taken in the positive sites. Results: A total of 13（5 sites in North Han River, 5 in Diaocha Lake, and 3 in Miaowu Ditch） surveillance and forecast sites were set up. No infected snail was detected in any of these sites in spring 2014. The detection rate of living snails in North Han River （18.7%, 224/1 201) was significantly higher than that in Diaocha Lake（12.8%, 852/6 644） and in Miaowu Ditch （6.4%, 202/3 147）（P<0.01）. Of the 520 mice placed, 6 were lost, and 514 were recovered, among which 4 mice died during laboratory raising. The remaining 510 sentinel mice were then dissected, revealing infection in 4 mice, with a positive rate of 0.8%. Twenty-seven Schistosoma japonicum worms were collected, and the mean worm burden of positive mice was 6.8 worms per mouse. Three sites (Sansi village, Kangjia village and Doubu village) were found to be positive sites of infection in September, with the detailed number of 2, 1 and 0 in North Han River, Diaocha Lake, and Miaowu Ditch respectively, with a positive rate of 1.5% （3/197）, 0.5% （1/195） and 0 （0/118） in sentinel mice （P>0.05）. In addition, among the 22 cattle found in the 13 sites, 2 were infected with schistosomes; and among the 62 fishermen and boatmen, 2 were infected. Emergency measures were taken in the three positive sites, and no high endemicity occurred. Conclusion: The monitoring of sentinel mice infections can improve the sensitivity of the surveillance and forecast system of schistosomiasis. The infected fishermen and cattle remain the major source of schistosomiasis transmission in Hanchuan City.

[Effect of comprehensive schistosomiasis control strategy based on infection source control in Hanchuan City].

OBJECTIVE: To evaluate the effect of comprehensive schistosomiasis control measures based on infection source control in Hanchuan City (marshland and lake endemic regions). METHODS: The data of comprehensive schistosomiasis control in Hanchuan City from 2004 to 2013 were collected, and the change trends of the Oncomelania hupensis snail status and the infection situation of human and livestock were analyzed to evaluate the control effect. RESULTS: After the implementation of the comprehensive measures, the infection rates of residents and cattle decreased from 6.38% and 8.11% in 2004 to 0.16% and 0 in 2013 respectively. There were no acute schistosomiasis patients since 2007, no new infection cases since 2011, and no infected snails since 2012. Compared with 2004, the occurrence rate of frames with living snails and the average density of living snails decreased by 56.78% and 68.35%, respectively, but the snail area and susceptible area increased by 0.62% and 7.10%, respectively. In 2013, all the 367 endemic villages in 26 townships reached the criteria of transmission controlled. CONCLUSIONS: The comprehensive schistosomiasis control measures based on infection source control can control the schistosomiasis transmission effectively in marshland and lake endemic regions. When consolidating the achievement, the snail area in inner embankment should be compressed to prevent the schistosome re-infection in human and livestock.

[Effects of different prevention and control measures on schistosomiasis prevalence in different limnetic regions].

OBJECTIVE: To compare the schistosomiasis control effects of the comprehensive control measures based on infectious resources control and the conventional control measures, so as to provide the evidence for improving prevention and control strategies. METHODS: In the Hanbei River basin, the comprehensive control measures based on infectious resources control (conventional measures plus grazing prohibition in the marshland, machine instead of cattle, and marshland development, and so on) were carned out, and in the Nanzhi River basin, the conventional control measures were performed. The schistosomiasis epidemic data were collected, analyzed and compared from 2004 to 2011. RESULTS: In 2004, the infection rate of the populations and cattle in Nanzhi River basin was lower than that in the Hanbei River basin. From 2004 to 2011, the Oncomelania hupensis snail frame occurrence rate and the average density of living snails in the Nanzhi River basin was lower than that in the non-ploughing marshland and preventing wave woods of the Hanbei River basin, and there were schistosome infected snails in the Nanzhi River basin. From 2008 to 2010, there were no infected snails in the non-ploughing marshland of the Hanbei River basin. From 2007, the cattle have been eliminated in the Hanbei River basin. From 2007 to 2011, there were no infected snails in the preventing wave woods of the Hanbei River, but there were schistosome infected cattle found by stool examinations every year in the Nanzhi River basin. From 2004 to 2011, the infection rates of population presented downward trends in the two river basins, but the downward trend was more significant in the Hanbei River basin than in the Nanzhi River basin. CONCLUSION: The conventional control measures and comprehensive control measures based on infectious resources control are both effective, but the latter is more effective.