ABSTRACT
OBJECTIVE: To understand the water infectivity of schistosome in key water regions of Wuhan City and explore the role of a sentinel mouse technique on surveillance and forecast system for schistosomiasis. METHODS: Schistosome-endemic areas of the Yangtze River, the Dongjing-Tongshun River system, the Fu-Lun River system and the Jinshui River of Wuhan City were chosen as the surveillance and forecast sites. The Oncomelania snail distribution and infection were surveyed before the flood season. The water infectivity was detected by using the sentinel mouse technique during the flood season. The infection status of people in the villages around the surveillance sites and the activities of human beings and domestic animals were surveyed. The correlation between the infection rate of sentinel mice and snail status was tested by the rank correlation method. The emergency response mechanism was initiated when the areas with schistosomes were detected in water. RESULTS: Among the 18 surveillance sites, 15 sites with infected sentinel mice were found, accounting for 83.33%. A total of 554 sentinel mice were placed and 540 recovered, with a recovery rate of 97.47%. All the recovered mice were dissected and 75 infected, with a total infection rate of 13.89%. Totally 172 adult worms were collected, with mean worm burden of 2.29 +/- 0.71 worms per mouse. The infection rates of sentinel mice in 4 water systems were 8.33%, 24.53%, 10.85% and 6.56%, respectively, and the mean worm burdens of infected sentinel mice were 2.33 +/- 0.71, 2.28 +/- 0.76, 2.22 +/- 0.60 and 2.75 +/- 0.96 worms per mouse, respectively. The infection rates of sentinel mice in 4 water systems had a statistically significant difference (chi2 = 19.131, P = 0.000). The mean worm burdens of the infected sentinel mice in 4 water systems had no statistically significant difference (F = 0.638, P = 0.593). The correlation coefficient among the infection rate of sentinel mice, snail area, the average density of living snails and infected snail rate had no statistical significance. Among the 15 sites with infected sentinel mice, 8 sites with fisherman activities, 8 sites with anglers or planters, 10 sites with cattle keepings and 4 of which with infected cattle. All the 15 sites with cercariae-infected water bodies started the emergency response and no epidemic situation happened. CONCLUSIONS: The water infectivity of schistosome in key water regions of Wuhan City was relatively high. Detecting water infectivity based on a sentinel mouse technique is an important part of surveillance and forecast system for schistosomiasis.
