Detection of spotted fever group (SFG) Rickettsia in Ixodes ricinus ticks from migrating passerine birds

Abstract

The spotted fever group (SFG) rickettsiae are intracellular bacteria usually associated with ixodid ticks. Birds are hosts of many tick species and may contribute to the dissemination of ticks and tick-borne pathogens throughout the world. However there is still a lack of data on the occurrence of ticks on birds and associated rickettsial pathogens in Baltic countries. A total of 146 birds of 15 species infested with ticks were collected at Ventes Ragas ornithological station, Lithuania during 2013 and 2014. The ticks were identified as Ixodes ricinus using standard morphological and molecular techniques. A total of 284 ticks (109 larvae and 175 nymphs) were examined for the presence of the SFG rickettsiae using PCR amplification and sequence analysis of gltA and 17kDa genes. Rickettsia DNA was detected in 10.2 % of the tick samples. Infected ticks were found on nine bird species Erithacus rubescula, Troglodytes troglodytes, Sylvia communis, Coccothraustes coccothraustes, Luscinia luscinia, Parus major, Phylloscopus collybita, Regulus regulus, Prunella modularis. E. rubescula were the predominant bird species infested by infected ticks. Sequence analysis of tested samples reveals presence of human pathogenic R. helvetica and R. monacensis with 98-100 % sequence similarity. This study is the first report of Rickettsia species in ticks from migrating passerine birds in Lithuania.