Abstract:

Objective To understand the status of schistosomiasis infection in wild rats in Guichi District, Chizhou City, for scientific evidence to formulate targeted schistosomiasis control strategies. Methods By the data of schistosomiasis epidemic situation in history in Guichi District and combined with the epidemic category and prevalence degree, we conducted annual survey in the wild rats in at least 10% of the endemic villages between 2020 and 2022. The rats living in the areas with snails were captured with mousetrap, and underwent parallel testing using microscopy examination for liver nodule, microscopy examination for mesenteric vein, Kato-Katz method, and miracidium hatching method. The related indicators, including the density of wild rats and schistosome infection rate, were summed up. Results Forty-six epidemic villages were surveyed from 2020 to 2022, and a total of 922 wild rats were captured. The density of wild rats was 6.91% (922/13 346), and the infection rate was 13.02% (120/922). The density and infection rate in the wild rats was 8.22% (245/2 982), 4.29% (217/5 058), and 8.67% (460/5 306); 3.27% (8/245), 14.29% (31/217), and 17.61% (81/460), respectively, in different years, with statistical significance (χ²=87.426, 29.455; all P<0.05), and 7.82% (589/7 534) and 16.98% (100/589) in hilly areas, 5.73% (333/5 812) and 6.01% (20/333) in lake and marshland areas (χ²=22.904, 22.398; all P<0.05). The largest number of wild rats captured was associated with Apodemus agrarius and Rattus losea Swinhoe, and respectively 15.10% (69/457) and 11.49% (40/348) of them were infected with schistosome. Conclusion Schistosoma japonicum infection exists in the wild rats living in hilly and lake areas in Guichi District, and the transmission risk of wild rats as a source of infection deserves attention.

Key words: Schistosomiasis, Wild rat, Sources of animal infections, Guichi District