Rickettsia species and their associations with rodents and their ectoparasites in Lithuania

Abstract

Rickettsiae are emerging pathogens causing public health problems in many countries around the world. Rickettsia spp. are found in association with a wide range of arthropods which feed on different species of animals. However, the distribution, natural cycle of Rickettsia species and their association with different arthropod vectors are not fully established. In this study, we report the occurrence and the molecular characterization of Rickettsia pathogens in eleven species of ectoparasites parasitizing small rodents in the Curonian Spit, West Lithuania. Altogether, 238 small rodents representing six species Apodemus fl avicollis, Myodes glareolus, Micromys minutus, Microtus oeconomus, M. agrestis and M. arvalis were trapped during 2013–2014. A total of 1261 ectoparasites (596 Ixodes ricinus ticks, 550 mites of fi ve species and 115 fl eas of eight species) were collected from these rodents. The overall prevalence of Rickettsia spp. in rodents was 27.6 %, with a higher prevalence detected in M. minutus (45.9%), followed by A. fl avicollis (32.8%), and M. glareolus (14.3%). The frequency of Rickettsia spp. infection in rodent-derived ectoparasites varied among species and was found highest in fl eas 43.5%, followed by I. ricinus ticks (MLE= 26.5%; CI 22.2-31.3), and mites (MLE=9.3%; CI 7.0-12.2). Sequence analysis of partial gltA and 17kDa genes revealed the presence of R. helvetica in rodents and R. helvetica , R. felis, R. monacensis, Rickettsia sp. and rickettsial endosymbiont in rodents ectoparasites. In fl eas four Rickettsia spp. were identifi ed, while in Laelapidae mites – three Rickettsia spp. In I. ricinus ticks only R. helvetica was found. This is the fi rst investigation of Rickettsia spp. in rodents and their ectoparasites in Baltic countries. Up to date, R. felis has never been identifi ed in Lithuania.[...]