New records of the Lyme disease bacterium in ticks collected from songbirds in central and eastern Canada

Abstract

This study highlights the collection of ticks from wild-caught birds in central and eastern Canada. Using polymerase chain reaction (PCR), 32 (33%) of 98 Ixodes species ticks tested were positive for the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.) Johnson, Schmid, Hyde, Steigerwalt, and Brenner (hereafter B. burgdorferi). Immature blacklegged ticks, Ixodes scapularis Say, which are competent vectors of B. burgdorferi, constituted the predominant Ixodes species tick collected from parasitized songbirds; specifically, 31(35%) of 89 I. scapularis nymphs were positive for B. burgdorferi. Notably, we report the first B. burgdorferi-positive I. scapularis (nymph) on a migratory passerine in Prince Edward Island; this is the first record of a tick on a bird in this maritime province. First-time records of B. burgdorferi-infected, I. scapularis nymphs on passerines in northwestern Ontario include rose-breasted grosbeak, Pheucticus ludovicianus (Linnaeus), eastern bluebird, Sialia sialis (L.), and indigo bunting, Passerina cyanea (L.). Similarly, we furnish a new host record in Canada for an I. scapularis (nymph) on a worm-eating warbler, Helmitheras vermivorus (Gmelin); this engorged nymph tested positive for B. burgdorferi. We document the first recorded collection of a B. burgdorferi-infected Ixodes muris Bishopp and Smith (female) on a songbird in Ontario. We provide the first account of a live culture of B. burgdorferi from an I. scapularis (nymph) collected from a brown-headed cowbird Molothrus ater (Boddaert) in Manitoba. We make available new host records for I. scapularis on a clay-coloured sparrow Spizella pallida (Swainson) and a Gambel's white-crowned sparrow Zonotrichia leucophrys gambelii (Nuttall). An I. scapularis on a songbird during southward autumn migration in northwestern Ontario is a first record reported. As well, we document the first-ever account of a reptile-associated tick, a nymph of Amblyomma sabanerae Stoll, on a veery Catharus fuscescens (Stephens) in northwestern Ontario. Migratory songbirds play an integral role in the wide dispersal of B. burgdorferi-infected ticks, especially during northward spring migration. Clinicians need to be aware that people can be bitten by B. burgdorferi-infected ticks released by songbirds across Canada.

Lyme Disease Bacterium, Borrelia burgdorferi Sensu Lato, Detected in Multiple Tick Species at Kenora, Ontario, Canada

“…In addition to mammals, resident and migratory songbirds disperse bird-feeding ticks in the area, especially during northward spring migration [8][9][10][11][12][13][14][15][16][17]. Not only do multiple host species support and maintain Lyme disease vector ticks, Neotropical and southern-temperate songbirds annually transport bird-feeding ticks (i.e., Ixodes affinis, Ixodes minor) into central Canada during spring migration from as far south as Brazil [10,11,15].…”

“…Songbirds (Passeriformes) can transport B. burgdorferi s.l.-infected I. scapularis larvae and nymphs to and from this bioregion during bi-directional migration in spring and fall [8][9][10][11][12][13][14][15][16][17]. Peak northward songbird migration in Canada occurs during May and early June, which coincides with peak questing periods of I. scapularis nymphs [47].…”

Detection of <i>Borrelia americana</i> in the Avian Coastal Tick, <i>Ixodes auritulus</i> (Acari: Ixodidae), Collected from a Bird Captured in Canada

“…During spring migration, several Ixodes ticks that originated from southern latitudes have been reported in Canada: an I. minor larva was collected from a Common Yellowthroat, Geothlypis trichas (Linnaeus) [37], I. affinis immatures have be collected from both Common Yellowthroat and Swainson's Thrushes, Catharus ustulatus (Nuttall) [22] [38], and many I. scapularis immatures have been collected from migratory songbirds during spring migration [22] [24] [33] [39]- [41]. Since all of these tick species are songbird-transported ticks, they can be imported into Canada annually during northward spring migration.…”

Lyme Disease Propelled by Borrelia burgdorferi-Infected Blacklegged Ticks, Wild Birds and Public Awareness ─ Not Climate Change

“…Not only are ground-foraging passerine migrants involved with the wide dispersal of immature stages of I. scapularis, raptors are also dispersing agents [27]. In central and eastern Canada, Scott and Durden found that 35% of the songbird-transported I. scapularis nymphs were infected with B. burgdorferi, and widely dispersed in nature [26]. Although global warming is claimed to be one of the contributing factors for enzootic B. burgdorferi transmission and tick expansion, migratory songbirds are actually the principal reason.…”

“…Moreover, Ogden et al speculates that climate change will induce northward tick expansion of blacklegged ticks in Canada [17], and propagate Lyme disease numbers, but their hypotheses are unsubstantiated. In actuality, the overriding factor in the wide dispersal of I. scapularis and B. burgdorferi in Canada are migratory songbirds [16,[18][19][20]26]. Not only are ground-foraging passerine migrants involved with the wide dispersal of immature stages of I. scapularis, raptors are also dispersing agents [27].…”