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 ( ) gene, three members of the sensu lato (Bbsl) complex were detected, namely a -like spirochete, sensu stricto (Bbss), and a distinct strain that may represent a separate Bbsl genospecies. This novel Bbsl strain was detected in a mouse tick, , collected from a House Wren, , in Quebec during the southward fall migration. The presence of Bbsl in bird-feeding larvae of suggests reservoir competency in three passerines (i.e., Common Yellowthroat, House Wren, Magnolia Warbler). Based on the 18S ribosomal RNA (rRNA) gene, three species (i.e., -like, , ) were detected in field-collected ticks. Not only was found in songbird-derived ticks, this piroplasm was apparent in adult questing blacklegged ticks, , in southern Canada. By allowing live, engorged ticks to molt, we confirm the transstadial passage of Bbsl in and in . Bbss and were detected concurrently in a groundhog tick, , in Western Ontario. In Alberta, a winter tick, , which was collected from a moose, , tested positive for Bbss. Notably, a -like piroplasm was detected in a rabbit tick, , collected from an eastern cottontail in southern Manitoba; this species is a first-time discovery in Canada. This rabbit tick was also co-infected with -like spirochetes, which constitutes a first in Canada. Overall, five ticks were concurrently infected with and Bbsl pathogens and, after the molt, could potentially co-infect humans. Notably, we provide the first authentic report of ticks co-infected with Bbsl and in Canada. The full extent of infectious microorganisms transmitted to humans by ticks is not fully elucidated, and clinicians need to be aware of the complexity of these tick-transmitted enzootic agents on human health. Diagnosis and treatment must be administered by those with accredited medical training in tick-borne zoonosis.