Are birds reservoir hosts for Borrelia afzelii?

It is known that birds are competent reservoir hosts of particular Borrelia species like B. garinii and B. valaisiana but not for B. afzelii, a rodent-associated genospecies. Since they can carry infected ticks over long distances, they are also important covectors for Lyme borreliosis spirochaetes. To assess the role of different bird species in transmission and dispersal of Borrelia OspA types, we examined 191 Ixodes ricinus ticks from 99 birds, captured on a German conservation island in the Baltic Sea in spring 2007. Surprisingly, more than one third of the 27 positive samples were identified as B. afzelii. The cause for this unusually high prevalence remains unknown, indicating the need of further studies on bird-feeding ticks that should include a higher sample size.