Abstract:

Objective To investigate the aggregation characteristics of rat fleas (Xenopsylla cheopis) on Asian house rats (Rattus tanezumi) and to provide scientific basis for plague control. Methods We collected fleas from live-trapped rats and calculated two infestation indices: flea prevalence and average flea abundance. Results A total of 73 rats were trapped from four survey sites along the Lancang River in Jinghong, Yunnan, and from these rats we collected 1 169 rat fleas. There were 1 056 fleas in a single survey site called Manfeilong Reservoir Fish Fry Field, with a flea prevalence of 95.45% and an overall average flea abundance of 48.00, showing an unusually super parasitic phenomenon. Moreover, we also found that the sex ratio of the fleas in this study was male-predominant, very different from previous reports (from either field surveys or lab breeding populations). Conclusion Since high densities of rat (R. tanezumi) and flea (X. cheopis) represent an increased risk in zoonotic plague prevalence, we suggest that there is a considerable high probability in causing the human plague in Jinghong, and local government and disease control department should be highly cautious about it.

Key words: Xenopsylla cheopis, Super parasite, Rattus tanezumi, Plague

摘要：

目的 调查黄胸鼠体表印鼠客蚤的群体集聚分布特征,为鼠疫的防治提供依据。方法 于2013年2月20日至3月2日,采用笼捕法捕获鼠类进行鼠体蚤采集,计算鼠体染蚤率和蚤指数。结果 在景洪市沿澜沧江两岸的4个调查点共捕获黄胸鼠73只,从其体表采集到印鼠客蚤1 169匹,其中在曼飞龙水库鱼苗场调查点获蚤1 056匹,染蚤率为95.45%,总蚤指数高达48.00,形成罕见的鼠体蚤高密度群体超寄生现象。调查还发现印鼠客蚤的雌雄性比与既往调查及实验室繁殖有明显差别。结论 较高的黄胸鼠、印鼠客蚤密度是鼠疫发生流行的重要条件。景洪市一段时间后再度暴发鼠疫的可能性依然存在,应引起云南省各级政府及疾病控制部门的高度关注。

关键词: 印鼠客蚤, 群体超寄生, 黄胸鼠, 鼠疫