Tick-borne pathogens in passerine migratory birds in Lithuania

Abstract

Migratory passerine birds are increasingly considered to be important in the global dispersal of tickborne pathogens. It is known that migratory bird caries ticks which is infected with Rickettsia spp, Borrelia spp, Anaplasma phagocytophilum and other tick-borne pathogens, but only a few studies are done to detect tick-borne infections in migratory birds. The aim of this study was to investigate tickborne pathogens in migratory birds. A total, 104 dead migratory birds belonged to 17 different species were collected from 2016 to 2018 years migrations in various Lithuania districts. For analysis heart, liver, spleen and brain samples from each individual were collected. Two multiplex real-time PCR assays were performed for detection of Anaplasma phagocytophilum, Borrelia spp, Babesia spp., Rickettsia spp. Bartonella spp. using as targets msp2, 23S rRNA, 18S rRNA, gltA and ssrA genes, respectively. Tick-borne pathogens were detected in different tissue of 9 bird species: Eurasian jay (Garrulus glandarius), Goldcrest (Regulus regulus), Great tit (Parus major), Coal tit (Parus ater), Song thrush (Turdus philomelos), Blackbird (Turdus merula), Yellowhammer (Emberiza citronela), European greenfinch (Chloris chloris) and Icterine warbler (Hippolais icterina). Only three pathogens A. phagocytophilum, Borrelia spp and Rickettsia spp. DNA were detected in 31% (33/104), 7.6% (8/104) and 7.6 % (8/104) examined birds, respectively. Coinfections with Anaplasma spp. and Borrelia spp. pathogens were found in 5.7% (6/104) individuals. These findings highlight the importance of migratory birds in circulation of tick-borne pathogens in Baltic region.