RESEARCH BY JOHN D. SCOTT
John D. Scott was chosen to receive a Sovereign’s Medal for Volunteers in recognition of 27 years of research and advocacy on Lyme disease and tick populations in Canada. He has published more than 30 peer-reviewed scientific articles on the topic.
Detection and Transstadial Passage of Babesia Species and Borrelia burgdorferi Sensu Lato in Ticks Collected from Avian and Mammalian Hosts in Canada
Lyme disease and human babesiosis are the most common tick-borne zoonoses in the Temperate Zone of North America. The number of infected patients has continued to rise globally, and these zoonoses pose a major healthcare threat. This tick-host-pathogen study was conducted to test for infectious microbes associated with Lyme disease and human babesiosis in Canada. Using the flagellin (flaB) gene, three members of the Borrelia burgdorferi sensu lato (Bbsl) complex were detected, namely a Borrelia lanei-like spirochete, Borrelia burgdorferi sensu stricto (Bbss), and a distinct strain that may represent a separate Bbsl genospecies. This novel Bbsl strain was detected in a mouse tick, Ixodes muris, collected from a House Wren, Troglodytes aedon, in Quebec during the southward fall migration. The presence of Bbsl in bird-feeding larvae of I. muris suggests reservoir competency in three passerines (i.e., Common Yellowthroat, House Wren, Magnolia Warbler).
Amblyomma dissimile Koch (Acari: Ixodidae) parasitizes bird captured in Canada.
November 30, 2015
We document Amblyomma dissimile Koch (Acari: Ixodidae) parasitizing a bird in Canada. A partially engorged A. dissimile nymph was collected from a Veery, Catharus fuscescens (Stephens) (Passeriformes: Turdidae), in Toronto, Ontario during spring migration. This constitutes the first authentic host record of A. dissimile on a bird in North America and, likewise, on a Veery, plus a new distributional record in Canada. Veeries could theoretically transport A. dissimile from as far south as southeastern Brazil, a distance of over 7,500 km. Experimentally, A. dissimile can transmit Ehrlichia ruminantium (Ricksettiales), which causes heartwater, a severe disease of cattle and other ungulates. Since a fully engorged A. dissimile nymph could likely molt during the summer in northern latitudes, this tick species could potentially parasitize local reptiles, people or ungulates, and cause autochtonous disease. Because A. dissimile is known to harbor rickettsiae in South America and is a laboratory vector of E. ruminantium, the medical and veterinary profession must be vigilant that A. dissimile may pose a health risk