Higher sika deer density is associated with higher local abundance ofHaemaphysalis longicornisnymphs and adults but not larvae in central Japan

Abstract

Haemaphysalis longicornis (Acari: Ixodidae) is one of the most common and important arthropod disease vectors in Japan, carrying Japanese spotted fever and bovine theileriosis. The recent expansion of sika deer (Cervus nippon, Artiodactyla: Cervidae) populations, the most common wild host of H. longicornis, has also caused concern about increasing the risk of vector-borne diseases in Japan. We used generalized linear mixed model analysis to determine the relative contribution of deer density and other biological and abiotic factors on the abundance of H. longicornis ticks questing at each developmental stage. A total of 6223 H. longicornis adults, nymphs, and larvae were collected from 70 sites in three regions of central Japan. The abundance of questing adult and nymphal ticks was associated with deer density and other biotic and abiotic factors. However, the abundance of questing larvae showed no association with deer density but did show an association with other biotic and abiotic factors. These findings show that a high density of deer along with other biotic and abiotic factors is associated with increased risk of vector-borne diseases through amplified local abundance of questing nymphal and adult H. longicornis. Further, questing larvae abundance is likely regulated by environmental conditions and is likely correlated with survival potential or the distribution of other host species.

Distinguishing Japanese Spotted Fever and Scrub Typhus, Central Japan, 2004– 2015

“…The difference in geographic distributions of JSF and ST may also be explained by the different distribution of the reservoirs in our study settings. Sika deer are wild hosts of ticks, and their distribution overlaps with that of ticks ( 25 ). The cluster of JSF identified in our study overlapped with the distribution of sika deer and Reeves’s muntjacs, which are related to sika deer ( 26 , 27 ).…”

Serological and molecular survey of tick‐borne zoonotic pathogens including severe fever with thrombocytopenia syndrome virus in wild boars in Miyazaki Prefecture, Japan

“…Considering the increasing habitat range of wild boars in the country (Ministry of the Environment Japan, 2015), this animal might contribute to changes in, or even the expansion of, endemic areas of these diseases by carrying vector ticks or the virus from their original habitats to other ecosystems. As the contribution of wild sika deer (Cervus nippon) to changes in tick fauna (Tsukada et al, 2014;Yamauchi et al, 2009) and the strong correlation between SFTSV seroprevalence in sika deer and the number of SFTS case reports in each endemic prefecture (Morikawa et al, 2016) have been demonstrated in the country, the involvement of wild boars in TBD outbreaks may also need to be brought to attention.…”

Mapping the Potential Distribution of Ticks in the Western Kanto Region, Japan: Predictions Based on Land-Use, Climate, and Wildlife

“…However, H. longicornis infestations on sika deer and correlations between questing height and sika deer height have been reported [56]. Tsukada et al [57] suggested the abundance of adult H. longicornis is affected by the abundance of sika deer. On the other hand, immature stages of H. longicornis are known to infest medium-and large-sized mammals including raccoons, tanuki, masked palm civets, Japanese badgers (Meles anakuma Temminck, 1844), and wild boars [47,[50][51][52][53][54].…”