Seabirds and the Circulation of Lyme Borreliosis Bacteria in the North Pacific

Seabirds act as natural reservoirs to Lyme borreliosis spirochetes and may play a significant role in the globalcirculation of these pathogens. While Borrelia burgdorferi sensu lato (Bbsl) has been shown to occur in tickscollected from certain locations in the North Pacific, little is known about interspecific differences in exposurewithin the seabird communities of this region. We examined the prevalence of anti-Bbsl antibodies in 805individuals of nine seabird species breeding across the North Pacific. Seroprevalence varied strongly amongspecies and locations. Murres (Uria spp.) showed the highest antibody prevalence and may play a major role infacilitating Bbsl circulation at a worldwide scale. Other species showed little or no signs of exposure, despitebeing present in multispecific colonies with seropositive birds. Complex dynamics may be operating in this widescale, natural host–parasite system, possibly mediated by the host immune system and host specialization of thetick vector.