目的 调查三峡库区重庆段鼠疫相关宿主动物和媒介蚤类的组成、分布及携带鼠疫病原体情况,预测当地发生鼠疫的潜在风险。方法 2017－2022年,在三峡库区重庆段沿线的涪陵、万州、开州、丰都、忠县、云阳、奉节和巫山共8个县（区）库区沿岸采用鼠笼法捕获小型兽类（小兽）,对所获小兽及其寄生蚤进行分类鉴定、记录和数据整理,采用描述性研究方法分析其群落结构特征,χ2检验或Fisher确切概率法用于比较组间差异。结果 共计布放鼠笼20 123笼次,捕获11种小兽共计403只,总密度为1.92%,其中黄胸鼠最多,构成比为62.28%,其次为小家鼠和褐家鼠,构成比分别为14.14%和8.68%,其余还有灰麝鼩（4.47%）、黑线姬鼠（3.47%）、四川短尾鼩（3.23%）、北社鼠（1.99%）、大足鼠（0.74%）、黄毛鼠（0.50%）、针毛鼠（0.25%）和小泡巨鼠（0.25%）,三峡库区重庆段8个县（区）小兽物种构成比差异有统计学意义（P<0.001）；8个调查县（区）中小兽密度以丰都县（2.88%）、涪陵区（2.71%）、奉节县（2.53%）和云阳县（2.52%）的相对较高,忠县（1.83%）、万州区（1.38%）、开州区（1.00%）的相对较低,各县（区）小兽密度差异有统计学意义（χ2=57.443,P<0.001）；体表染蚤小兽共计151只,捕获寄生蚤3种共1 034匹,总染蚤率为37.47%,总蚤指数为2.57,不同县（区）的小兽染蚤率差异有统计学意义（χ2=54.534,P<0.001）,有8种小兽染蚤,染蚤率差异有统计学意义（P=0.003）。所获蚤类中绝大多数为缓慢细蚤,共计1 031匹,其余为2匹不等单蚤,1匹猫栉首蚤；403只活鼠全部采血,进行鼠疫菌F1血清抗体检测,结果均为阴性。结论 目前三峡库区重庆段发生动物间和人间鼠疫流行的风险较低,但仍应持续监测,警惕家、野栖小兽及其体表寄生蚤类的种群交互传播,以及外来物种输入引起鼠疫等鼠传疾病传播的风险。
Objective To investigate the species composition and distribution of host animals and vector fleas of Yersinia pestis in Chongqing section of the Three Gorges Reservoir area, evaluate the presence of Y. pestis in these animals, and predict the potential risk of plague occurrence in the area. Methods From 2017 to 2022, an investigation was carried out in eight districts or counties along the Chongqing section of the Three Gorges Reservoir area, namely Fuling, Wanzhou, Kaizhou, Fengdu, Zhong County, Yunyang, Fengjie, and Wushan. Small mammals were captured by cage trapping method alongside the reservoir. The small animals and their parasitic fleas were identified and recorded. The data were used for descriptive analysis of their community structure characteristics. Chi-square test or Fisher's exact test was used to analyze differences between groups. Results A total of 403 small animals of 11 species were captured in 20 123 cage traps. The total density was 1.92%. Rattus tanezumi was the dominant species (62.28%), followed by Mus musculus (14.14%), R. norvegicus (8.68%), Crocidura attenuate (4.47%), Apodemus agrarius (3.47%), Anourosorex squamipes (3.23%), Niviventer confucianus (1.99%), R. nitidus (0.74%), R. losea (0.50%), N. fulvescens (0.25%), and Leopoldamys edwardsi (0.25%). The species composition of small mammals in 8 districts and counties in Chongqing section of the Three Gorges Reservoir area showed significant differences (P<0.001). The small mammal density was relatively high in Fengdu County (2.88%), Fuling District (2.71%), Fengjie County (2.53%), and Yunyang County (2.52%). The density was relatively low in Zhong County (1.83%), Wanzhou District (1.38%), and Kaizhou District (1.00%). The small mammal density was significantly different among 8 districts and counties (χ2=57.443, P<0.001). A total of 151 small mammals carried ectoparasitic fleas. A total of 1 034 parasitic fleas in 3 species were captured. The total flea infection rate was 37.47%, and the total flea infection index was 2.57. In addition, the flea infection rates were significantly different among districts and counties (χ2=54.534, P<0.001). Eight small animal species were infected with fleas, and their flea infection rates were significantly different (P=0.003). The vast majority of captured fleas were Leptopsylla segnis (1 031 individuals), 2 fleas were Monopsyllus anisus, and 1 flea was Ctenocephalides felis. Blood samples collected from all 403 live rodents tested negative for the serum antibody of Y. pestis F1. Conclusions The risk of plague epidemic among animals and humans is relatively low in the Chongqing section of the Three Gorges Reservoir area. However, continuous surveillance should be conducted to remain vigilant for the potential risk of plague and other rodent-borne diseases caused by the mixing of populations of domestic and wild small mammals and their ectoparasitic fleas, as well as the introduction of non-native species.
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