Borreliae in immature Ixodes ricinus (Acari:Ixodidae) ticks parasitizing birds in the Czech Republic.

Of 411 forest birds of 33 species examined near Valtice, Czech Republic, 29% were infested with Ixodes ricinus (L.); 2.2% were parasitized by Haemaphysalis concinna Koch. Borreliae were detected in 5.1 and 11.7% of larval and nymphal I. ricinus, respectively. None of the 13 H. concinna tested was infected. In total, 3.2% of the birds examined were parasitized by I. ricinus immatures infected by borreliae. Borreliae-containing ticks parasitized European robin, Erithacus rubecula (L.); Eurasian blackbird, Turdus merula L.; Blackcap, Sylvia atricapilla (L.); Eurasian chiffchaff, Phylloscopus collybita (Vieillot); Great tit, Parus major L.; and Eurasian jay, Garrulus glandarius (L.). The isolate BR-34 from a nymphal I. ricinus off a Eurasian blackbird had a sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein pattern, reactions to monoclonal antibodies, and fragments of HindIII digested DNA probed with fla and ospA genes that suggested to us that it belongs to the genospecies Borrelia garinii. Free-living birds may be involved in the circulation of B. burgdorferi sensu lato principally as disseminators of infected ixodid ticks to new area.