Investigation of Babesia spp. in sympatric populations of Dermacentor reticulatus and Ixodes ricinus ticks in Lithuania and Latvia

The objectives of the present study were to investigate the presence of the Babesia parasites in Dermacentor reticulatus ticks along its current distribution range in Lithuania and Latvia, and Ixodes ricinus in Lithuania, to characterize the detected Babesia spp. using partial sequencing of 18S rRNR gene, and to determine the prevalence of the Babesia pathogens in ticks from different locations of Lithuania and Latvia. From 2013 to 2015, four D. reticulatus nymphs and 2255 questing adults were collected from 40 locations in Lithuania, and 181 questing adult D. reticulatus specimens from 11 locations in Latvia. In Lithuania, 16 questing I. ricinus nymphs and 354 questing adults were collected from 12 locations with the sympatric existence of D. reticulatus and I. ricinus. In Lithuania, Babesia spp. were detected in 1.2% (26/2259) of D. reticulatus and in 9.5% (35/370) of I. ricinus ticks. The overall prevalence of Babesia in D. reticulatus ticks from Latvia was 2.8% (5/181). Sequence analysis of partial 18S rRNA gene of positive samples indicated the presence of B. canis and B. venatorum in D. reticulatus ticks, whereas B. microti and B. venatorum were detected in I. ricinus ticks. Our study is the first investigation on the prevalence and molecular characterization of zoonotic B. canis, B. venatorum, and B. microti in ixodid ticks in Lithuania, and of B. canis in D. reticulatus ticks in Latvia. It is also the first report of B. venatorum in D. reticulatus ticks.