Lyme disease diversity in Canada

The Lyme disease bacteri­um has considerable variation across Canada. Using DNA testing, re­searchers found wide genetic dif­ference in Lyme disease bacteria contained in vector ticks that were removed from songbirds nationwide.

Three new Lyme strains were collected from two different tick species along coastal British Columbia. Of note, re­searchers report the first time account of a Lyme-carry­ing mouse tick collected from a songbird anywhere; the tick was col­lec­ted from a white throated spar­row in northern Nova Scotia.

During the nationwide bird-tick study, Lyme disease bac­teria were isolated from four different tick species. Re­searchers suggest common yellowthroat, golden crowned spar­row, song sparrow, and Swainson’s thrush are hosts that carry Lyme disease bac­teri­um in their bodies, and transmit its parasite ticks.

The three year study re­vealed songbirds trans­port Lyme positive ticks north­ward into Canada during spring mi­gration and carry them to north­ern Canadian latitudes from tick populations along the southern fringe of Canada.

Ticks were transported by songbirds as far north as the Yukon. One rare species  was imported by a gray catbird during migratory flight from as far south as Central America.

Locally, a Lyme-infected tick was collected from a com­mon yellowthroat in Toronto. The study concludes that people do not have to go to an endemic area to contract Lyme disease.

John Scott, of Fergus, is a researcher with Lyme Disease Association of Ontario. He recently presented the Fergus library with Ending Denial: The Lyme Disease Epidemic, A Canadian Public Health Dis­aster, by Helke Ferrie.

 

 

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