关键词:  鼠疫疫源地, 鼠形动物, 寄生蚤, 丰盛度, 宿主种类, 身体特征, 环境因子；气象因子

Abstract: 【Aim】 To analyze the predictors of the abundance of parasitic fleas on wild myomorph rodents in the Yulong plague focus of Yunnan Province, southwestern China. 【Methods】 Field rodent trapping was carried out in three altitudes and four seasons of plague foci in Yulong County, Yunnan Province. The parasitic fleas on myomorph rodents were collected by comb method and identified under a microscope. Data of potential predictors of the abundance of parasitic fleas, including characters of myomorph rodents (such as species, age, gender, body length, and weight) and environmental factors (such as altitude and season), were collected through measurement and observation. Data set was established using EpiData 3.0.2. The relationship between the abundance of parasitic fleas and the potential predictors was explored using hurdle negative binomial regression model under R software. 【Results】 A total of 484 parasitic fleas belonging to nine species were collected from 884 myomorph rodents. Among them, Neopsylla specialis specialis, Ctenophthalmus quadrates, Macrostylophora euteles and Ctenophthalmus yunnanus fleas are dominant, with their individual number accounting for 86.16% of the total number of individuals of fleas. Regression analysis revealed that the probability of flea infestation at 2 700-3 000 m and above 3 000 m increased by 1.27 and 3.72 times as compared with that at 2 400-2 700 m, respectively. The probability of flea infestation under the humidity over 70% decreased by 41% as compared with that under the humidity not exceeding 70%. The probability of flea infestation on Apodemus draco reduced by 50% as compared with that on Apodemus chevrieri, while the probability of flea infestation on Eothenomys miletus increased by 79%. The probability of flea infestation on myomorph rodents with the body length exceeding 104 mm increased by 76% as compared with that on myomorph rodents with the body length less than or equal to 104 mm. When air temperature exceeded 15℃, the number of fleas on myomorph rodents decreased by 67% as compared with that at the air temperature not exceeding 15℃. The number of fleas on adult myomorph rodents increased by 2.25 times as compared with that of immature myomorph rodents. The number of fleas in summer increased by 2.00 times, the probability of flea infestation in autumn decreased by 48%, and the probability of flea infestation and the number of fleas in winter increased by 1.44 and 1.06 times, respectively, as compared with those in spring. 【Conclusion】 Neopsylla specialis specialis, Ctenophthalmus quadrates, Macrostylophora euteles and Ctenophthalmus yunnanus are the dominant species of parasitic fleas on wild myomorph rodents in the Yulong plague focus. The abundance of parasitic fleas is closely related to the environmental factors such as altitude, season, air temperature and humidity, and the characters of myomorph rodents such as species, body length, and age.

Key words:  Plague focus, myomorph rodents, parasitic fleas, abundance, host species, body characters, environmental factors, meteorological factors