Abstract:

Objective To investigate the prevalence of Schistosoma japonicum infection in wild mice in Ma'anshan City, so as to provide a scientific basis for precise control of schistosomiasis. Methods From September 2021 to November 2022, we conducted a field survey based on the historical epidemic data of schistosomiasis in Ma'anshan City in partial key environments in the townships confirmed with presence of infected snails by Loop-mediated isothermal amplification (LAMP) method in the past three years for the distribution of wild mice and the status of schistosomiasis infection. Mousetraps were used to overnight capture the mice. Parallel examinations were conducted on captured wild mice using liver compression microscopy, liver homogenate microscopy, mesenteric vein compression microscopy, Kato-Katz method, and miracidium hatching method. Finally, the relevant indicators, including the density of wild mice and Schistosoma japonicum infection rate, were analyzed. Results Fifteen key environments were selected from 4 townships (communities) in this survey, and a total of 343 wild mice were captured. The average density was 6.40% (343/5 362) for the wild mice. The density of wild rodents in each township (community) was 12.43% (69/555) in Jinjiazhuang Community of Huashan District, 9.62% (50/520) in Jiashan Town of Yushan District, 6.76% (148/2 188) in Huyang Town, and 3.62% (76/2 099) in Huangchi Town of Dangtu County. The overall mouse density was different among the townships (χ²=70.271, P<0.05). Three hundred and twenty-six valid wild mouse samples were obtained, including 173 Rattus losea, 122 Apodemus agrarius, 23 Rattus norvegicus, 7 Mus musculus and 1 Niviventer fulvescens. Thirty-six wild mice were detected to be infected with Schistosoma japonicum. The infection was seen in Huyang Town and Huangchi Town of Dangtu County, with an infection rate of 18.57% (26/140) and 13.16% (10/76), respectively, for the mice captured in the two areas aforementioned, yet the difference was insignificant (χ²=1.039, P>0.05). The wild mouse species in Huyang Town with positive results were Rattus losea, Apodemus agrarius, Rattus norvegicus and Mus musculus, with infection rate of 22.00% (22/100), 6.45% (2/31), 33.33% (1/3) and 20.00% (1/5), respectively, and there was no statistical differences (Fisher's exact probability method, P>0.05). The wild mouse species in Huangchi Town detected to be positive included Rattus losea and Apodemus agrarius. The infection rate was 20.59% (7/34) and 13.64% (3/22), respectively, without statistical significance (χ²=0.094, P>0.05). Conclusion Wild mice may be one of the important sources of infection for schistosomiasis in Ma'anshan area. In the future, we should continue to strengthen the monitoring of wild rodents in epidemic areas, carry out snail control in key environments, and timely drop the wild mouse density by application of integrated measures, such as rodent control and environmental improvement, to further reduce the risk of schistosomiasis transmission.

Key words: Wild mice, Schistosoma japonicum, Infection rate, Ma'anshan City