Infection Prevalence of &amp;lt;i&amp;gt;Borrelia burgdorferi&amp;lt;/i&amp;gt; in Ticks Collected from Songbirds in Far-Western Canada

John D Scott,John F Anderson,Lance A Durden

doi:10.4236/ojas.2015.53027

Abstract

Worldwide, wild birds play a vital role in the dispersal of ticks that harbour tick-borne pathogens, including Borrelia burgdorferi, the Lyme disease bacterium. Using PCR testing, we found 124 (31%) of 405 ticks (4 species), which were collected from 21 species of birds in far-western Canada, to be infected with B. burgdorferi. Transstadial transmission of B. burgdorferi occurred from larva to nymph, plus nymph to adult, in the avian coastal tick, Ixodes auritulus, collected from songbirds in British Columbia (B.C). Collectively, all 3 motile life stages (larva, nymph, adult) of this tick had an infection prevalence of 31% for B. burgdorferi, which suggests vector competency. A Pacific Wren was highly infested with I. auritulus immatures, and 20 (44%) of 45 ticks (2 nymphs, 43 larvae) were infected with B. burgdorferi. This heavy infestation shows the high potential to initiate a new population of ticks and to disseminate Lyme spirochetes. Epidemiologically, B. burgdorferi-infected I. auritulus larvae collected from the Spotted Towhee, Swainson’s Thrush, Pacific Wren, and Fox Sparrow suggest that these avian hosts act as reservoirs for B. burgdorferi. In this study, the western blacklegged tick, Ixodes pacificus, and Ixodes spinipalpis played a limited role in the enzootic transmission cycle of B. burgdorferi along coastal B.C. We document the first record of I. spinipalpis on a bird in Alberta. Because songbirds widely disperse Lyme disease vector ticks, primary health providers and the general public must be vigilant that outdoors people may be bitten by B. burgdorferi-infected ticks throughout far-western Canada.

Highlights

Worldwide, Lyme disease (Lyme borreliosis) is present in more than 80 countries, and the causative agent infects a wide diversity of vertebrates, including wild birds
Because songbirds widely disperse Lyme disease vector ticks, primary health providers and the general public must be vigilant that outdoors people may be bitten by B. burgdorferi-infected ticks throughout far-western Canada
Passerine birds, commonly called songbirds, are hosts for certain hard-bodied ticks (Ixodida: Ixodidae) that carry pathogenic microorganisms. These blood-sucking ectoparasites carry a wide group of tick-borne pathogens, including the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.) Johnson, Schmidt, Hyde, Steigerwalt & Brenner ( B. burgdorferi) [2]

Summary

Introduction

Lyme disease (Lyme borreliosis) is present in more than 80 countries, and the causative agent infects a wide diversity of vertebrates, including wild birds. Passerine birds (order: Passeriformes), commonly called songbirds, are hosts for certain hard-bodied ticks (Ixodida: Ixodidae) that carry pathogenic microorganisms. These blood-sucking ectoparasites carry a wide group of tick-borne pathogens, including the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.) Johnson, Schmidt, Hyde, Steigerwalt & Brenner ( B. burgdorferi) [2]. Tick researchers reported the avian coastal tick, Ixodes auritulus Newmann; the mouse tick, Ixodes muris Bishopp and Smith; the western blacklegged tick, Ixodes pacificus Cooley & Kohls; and Ixodes spinipalpis Hadwen & Nuttall, as ectoparasites of passerines in British Columbia [3] [4]. Gregson [6] reported I. auritulus, I. pacificus, and I. spinipalpis in far-western Canada and, of these, I. auritulus and I. spinipalpis were recorded on passerines

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