[Surveillance results and risk analysis of Schistosoma japonicum-infected sentinel mice in key water regions in Hubei Province in 2016].

Objective To investigate the water infectivity in key water regions, and analyze the transmission risk of schistosomiasis in suspicious and high-risk environments in Hubei Province in 2016. Methods Schistosome-endemic areas of the Yangtze River, the Hanbei River and the Fu River were chosen as the surveillance and forecast sites. The water infectivity was detected by using the sentinel mice during the flood season. The infection status of residents in the villages around the surveillance sites and the activities of human beings and domestic animals were surveyed. The emergency response system was initiated when the water infectivity areas were detected. Results From May to June, among the ten surveillance sites of the first batch, two positive spots with infected mice were found, accounting for 20%. All the recovered mice (totally 200) were dissected: five mice were infected, with a total infection rate of 2.5%. Totally five schistosome adult worms were collected, with mean worm burden of 1 worm per infected mouse. The site with cercariae-infected water body started the emergency response and no epidemic occurred. From August to September, among the eight surveillance sites of the second batch, the recovered mice (totally 160) were dissected, and no infected sentinel mice were found. Conclusion The sentinel mice method plays an important role in analyzing the schistosomiasis transmission risk in Hubei Province.

[Molluscicidal effect of suspension concentrate of niclosamide ethanolamine salt].

Objective To evaluate the molluscicidal effect of suspension concentrate of niclosamide ethanolamine salt (SCNE) against Oncomelania hupensis snails in laboratory and field. Methods The experiment of SCNE against the snails by using the immersing and spraying methods was performed in laboratory and field, with control groups of wettable powder of niclosamide ethanolamine salt (WPN). Results In the laboratory, LC50(s) of SCNE for 24, 48 h and 72 h by using the immersion method were 0.092 6, 0.062 9 mg/L and 0.054 9 mg/L, respectively. The mortality rates of snails for 24, 48 h and 72 h by using the immersion method were all 100% with the concentrations of 0.25 mg/L. The mortality rates of snails were all 100% while spraying SCNE for 3 d in the laboratory with the concentrations of 0.25 g/m2. In Jiangling County, except 0.5 g/m3 SCNE immersing the snails for 24 h, the mortality rates of snails by using SCNE with the immersing method were all 100%. While the concentration of SCNE was 0.5 g/m3 or above, the mortality rates were all 100% after the use of it with the immersion method for 2 d in Gong'an County. In Jiangling County, the mortality rates of snails by using SCNE 0.5 g/m3 for 1 d, 3 d, and 7 d with the spraying method were 87.5%, 92.82% and 97.40% respectively. While the concentration of SCNE was 0.5 g/m3, the mortality rates were 85.94%, 86.78% and 94.21% respectively after the use of it with the spraying method for 1 d, 3 d, 7 d in Gong'an County, and the molluscicidal effect of SCNE (1.0 g/m2) was higher than that of WPN. Conclusion SCNE has a high molluscicidal effect in the laboratory and field, and it is a novel and simple formulation of niclosamide.