Differences in Tick Infestation Intensity by Season, Sex, Age Class, and Body Region of Feral Raccoons (Procyon lotor) in the Miura Peninsula, Japan

Abstract

The raccoon (Procyon lotor) is an invasive species in Japan and has been identified as a susceptible host and reservoir of tick-borne diseases. In our study conducted on the Miura Peninsula, Kanagawa Prefecture, Japan, a total of 47604 ticks were collected from 253 raccoon carcasses (92.3% of raccoons). The predominant tick species found was Haemaphysalis flava, constituting 97.4% of the collected ticks, followed by eight other species from three genera. Generalized linear mixed models with raccoon sex, age, season, and land use at the captured site as explanatory variables indicated that raccoon sex and seasonal variations were significant factors influencing tick infestations across all stages and sexes of H. flava. Raccoon age indicated an impact on adult and larval H. flava. Additionally, the land use was relevant only for the model of nymph, with urban areas being a significant factor. Our analysis suggests that male raccoons have a substantial role for increasing and spreading ticks. We also noted a significant concentration of ticks infesting ears and head of raccoons. These findings contribute to the development of efficient and quantitative evaluation methods for tick infestation towards disease prevention strategies in wildlife management.