The first detection of Babesia EU1 and Babesia canis canis in Ixodes ricinus ticks (Acari, Ixodidae) collected in urban and rural areas in northern Poland.

Ixodes ricinus, the most commonly observed tick species in Poland, is a known vector of such pathogenic microorganisms as TBE viruses, Borrelia burgdoferi sensu lato, Anaplasma phagocytophilum, Rickettsia helvetica, Babesia divergens and B. microti in our country. Our study aimed to find out whether this tick can also transmit other babesiae of medical and veterinary importance. DNA extracts of 1392 ticks (314 nymphs, 552 male and 526 female ticks) collected in urban and rural areas in the Pomerania province (northern Poland), were examined by nested PCR for the detection of Babesia spp., using outer primers: 5-22F and 1661R, and inner primers: 455-479F and 793-772R, targeting specific fragment of 18S rRNA gene. Overall, at least 1.6% ticks were found to be infected with babesial parasites. In the case of nymphs, the minimal prevalence was 0.6%, and it was approx. 3-times lower than in adults (1.9%). Percentages of infected males and females were comparable (2.0% vs. 1.7%). Sequences of 15/22 PCR-derived fragments of 18S rRNA gene demonstrated 100% similarities with the sequence of Babesia EUI (proposed name B. venatorum) (acc. no. AY046575) (n = 13) and with B. canis canis (acc. no. AY321119) (n = 2), deposited in the GenBank database. The partial 18S rDNA sequences of Babesia EUI and B. c. canis obtained by us from I. ricinus have been deposited in GenBank, accession nos. GQ325619 and GQ325620, respectively. The results obtained suggest the possible role of I. ricinus as a source of microorganisms, which have been identified as agents of human and canine babesiosis, respectively, in Europe. To our knowledge this is the first report on the occurrence of Babesia EUI and B. c. canis in I. ricinus in Poland.