The Establishment of a Blacklegged Tick Population by Migratory Songbirds in Ontario, Canada

John Scott

doi:10.13188/2325-4645.1000005

Abstract

This 2-year study implicates migratory songbirds in the initiation of an inland Lyme disease endemic area in southeastern Ontario. The spirochetal bacterium, Borrelia burgdorferi sensu lato Johnson, Schmid, Hyde, Steigerwalt & Brenner, which causes Lyme disease, was detected in blacklegged ticks, Ixodes scapularis Say, collected by flagging. Based on PCR amplification, 19 (33.3%) of 57 I. scapularis adults (males, females) were infected with B. burgdorferi. Since transovarial transmission of B. burgdorferi is nil in I. scapularis and white-tailed deer. Odocoileus virginianus Zimmermann, are not reservoir-competent hosts, we suggest that songbirds are the mode of introduction of B. burgdorferi-infected I. scapularis. All of the natural abiotic and biotic attributes are present to establish a Lyme disease endemic area. Blacklegged ticks survived the winter successfully at the epicentre. We provide substantial evidence that migratory songbirds initially introduced Lyme disease vector ticks and B. burgdorferi spirochetes to this remote woodland habitat and initiated an established population of blacklegged ticks.

Highlights

Submission: 04 January 2014 Accepted: 27 January 2014 Published: 30 January 2014 acts as a zoonotic vector of several human pathogens: Anaplasma phagocytophilum [41], Babesia spp. (e.g., B. microti, human babesiosis) [42], Bartonella spp. (e.g., B. henselae bacteremia) [43,44,45], Borrelia miyamotoi [46], deer tick virus (Powassan virus group) [47], Ehrlichia phagocytophila [48], and Mycoplasma spp. (e.g., M. fermentans) [49].Certain songbirds are reservoir-competent hosts of B. burgdorferi
Immatures of I. scapularis parasitize at least 76 different bird species, especially passerines (Order: Passeriformes), primarily perching birds [4,5,6,7,8,9,10,11]. This tick species has been collected from migratory songbirds as far west and north as the town of Slave Lake, Alberta [7] and, a B. burgdorferi-positive I. scapularis nymph was detached from a passerine migrant in central Saskatchewan (Tweedsmuir, SK) [3]
B. burgdorferi has been isolated from partially- and fully-fed I. scapularis larvae parasitizing songbirds, which compliments the fact that these avian hosts are reservoirs of infection, and can potentially initiate new Lyme disease foci [52]

Summary

Introduction

Submission: 04 January 2014 Accepted: 27 January 2014 Published: 30 January 2014 acts as a zoonotic vector of several human pathogens: Anaplasma phagocytophilum (human granulocytic anaplasmosis) [41], Babesia spp. (e.g., B. microti, human babesiosis) [42], Bartonella spp. (e.g., B. henselae bacteremia) [43,44,45], Borrelia miyamotoi (relapsing fever group spirochete) [46], deer tick virus (Powassan virus group) [47], Ehrlichia phagocytophila (granulocytic ehrlichiosis [E. equi group]) [48], and Mycoplasma spp. (e.g., M. fermentans) [49]. The blacklegged tick, Ixodes scapularis Say (Ixodida: Ixodidae), is burgdorferi in its body for 6 months and, as a result, engorging larval the primary vector of the Lyme disease-spirochete, Borrelia burgdorferi and nymphal I. scapularis can subsequently become infected. Immatures (larvae, nymphs) of I. scapularis parasitize at least 76 different bird species, especially passerines (Order: Passeriformes), primarily perching birds (songbirds) [4,5,6,7,8,9,10,11]. B. burgdorferi has been isolated from partially- and fully-fed I. scapularis larvae parasitizing songbirds, which compliments the fact that these avian hosts are reservoirs of infection, and can potentially initiate new Lyme disease foci [52]. In addition to Lyme disease spirochetes, the blacklegged tick songbirds can transport B. burgdorferi-infected I. scapularis into a Citation: Scott JD, Scott CM, Anderson JF. ISSN: 2325-4645 new geographic area, and provide the essential enzootic components to establish a Lyme disease endemic area

Materials and Methods

Results

Discussion