Clin Microbiol Infect 2011; 17: 918–920
Bartonella (B.) henselae is the zoonotic agent of cat scratch disease. B. henselae has been associated with therapy-resistant Lyme disease in humans suggesting that B. henselae and Borrelia burgdorferi sensu lato might be transmitted concurrently by ticks. In the present study we found that 16 (6.9%) of 230 Ixodes ricinus collected from humans harboured DNA of Bartonella spp. Fifteen positive ticks were infected with B. henselae and one tick with B. clarridgeiae. Twenty-five percent of the 16 Bartonella positive ticks were co-infected with Borrelia burgdorferi sensu lato. Our data show that B. henselae is present in Ixodes ricinus and that ticks may serve as source of infection for humans.