First Detection of Lyme Disease Spirochete Borrelia burgdorferi in Ticks Collected from a Raptor in Canada

During a pan‒Canadian tick‒host study, the authors detected the spirochetal bacterium Borrelia burgdorferi sensu lato, which causes Lyme disease, in ticks from a raptor. Lyme disease is one of a number of zoonotic, tick‒borne diseases causing morbidity and mortality worldwide. Larvae of the avian coastal tick, Ixodes auritulus, were collected by wildlife rehabilitators from a Cooper’s hawk, Accipter cooperii, on Vancouver Island, British Columbia. Using PCR [polymerase chain reaction] amplification of the linear plasmid ospA gene of B. burgdorferi, 4 (18%) of 22 larvae were positive. Since these engorged I. auritulus larvae had not had a previous blood meal and B. burgdorferi is rarely transmitted from infected female ticks to their progeny, authors propose that Cooper’s hawks are reservoir‒ competent hosts of B. burgdorferi. Authors’ tick‒host discovery provides the first report of bird‒feeding ticks on a Cooper’s hawk, and exhibits the premier record of B. burgdorferi‒positive ticks on a raptor. Not only are passerine (perching) and gallinaceous (chicken‒like) birds included in the wide dispersal of Lyme disease vector ticks, raptors also now are implicated in the dissemination of B. burgdorferi‒infected ticks. Although I. auritulus does not bite humans, this tick species plays an integral role in the four‒tick enzootic cycle of B. burgdorferi along the West Coast of America. In essence, raptors and I. auritulus ticks may help to amplify this infectious agent in nature, and increase the likelihood of people contracting Lyme Disease, especially in coastal areas.