Prevalence and patterns of ectoparasites infesting Pallas's squirrels (Callosciurus erythraeus) in Kanagawa Prefecture, Japan.

The Pallas's squirrel (Callosciurus erythraeus) has invaded fragmented woodlands in urban areas of Kanagawa Prefecture, where frequent human contact occurs. We examined 538 squirrels in Hayama-machi, Kanagawa Prefecture, for ectoparasite infestations. A total of 1,164 lice, 877 fleas, and 231 ticks were retrieved from 297 (55.2%), 338 (62.8%), and 135 (25.1%) squirrels, respectively. The identified ectoparasite species were Neohaematopinus callosciuri, Ceratophyllus anisus, Haemaphysalis flava, Haemaphysalis hystricis, and Ixodes turdus. The prevalence of N. callosciuri and C. anisus was significantly higher in adult males (N. callosciuri 63.6%, C. anisus 70.4%) than that in adult females (N. callosciuri 36.1%, C. anisus 49.0%; P<0.0001). Such information on the dynamics of host-ectoparasite relations is crucial for evaluating the risk to public health.