[Epidemiology of Ixodes-Borreliosis in Southern Germany]

Intimate adaptation occurs between European strains of Borrelia burgdorferi and the local hard tick Ixodes ricinus. I. dammini, the important vector in USA, could not be infected experimentally with a strain of the lyme spirochete from Southern Germany. Other species of blood suckers are sometimes able to maintain uptaken spirochetes for a few days, but never to compensate the tick vector. Man seems to be a good host for B. burgdorferi but without epidemiological significance due to his poor vector role for ticks. The Ixodes-borreliosis is an anthropozoonosis. Well-known animal hosts for the three life stages of the tick are possible carrier hosts for B. burgdorferi as well. It has been established here for the first time in Europe that common wild-rodent species may be of some significance as hosts for the spirochete, as it is well-known in North America. Serological evidence shows, that dogs and grasing cattle in Southern Germany seem to play an important role in B. burgdorferi's outdoor circulation. 36 out of 72 dogs (= 50%) and 22 out of 66 cattle (= 33%) reacted significantly positive in the IFAT if local strains of B. burgdorferi were used as antigen. No serological cross reactions have been observed with Leptospira infections in dogs and cattles.