Detection and Transstadial Passage of Babesia Species and Borrelia burgdorferi Sensu Lato in Ticks Collected from Avian and Mammalian Hosts in Canada
John D. Scott 1,*, Kerry L. Clark 2, Nikki M. Coble 2 and Taylor R. Ballantyne 2
Received: 24 October 2019; Accepted: 26 November 2019; Published: 2 December 2019
Abstract: 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). Based on the 18S ribosomal RNA (rRNA) gene, three Babesia species (i.e., Babesia divergens-like, Babesia microti, Babesia odocoilei) were detected in field-collected ticks. Not only was B. odocoilei found in songbird-derived ticks, this piroplasm was apparent in adult questing blacklegged ticks, Ixodes scapularis, in southern Canada. By allowing live, engorged ticks to molt, we confirm the transstadial passage of Bbsl in I. muris and B. odocoilei in I. scapularis. Bbss and Babesia microti were detected concurrently in a groundhog tick, Ixodes cookei, in Western Ontario. In Alberta, a winter tick, Dermacentor albipictus, which was collected from a moose, Alces alces, tested positive for Bbss. Notably, a B. divergens-like piroplasm was detected in a rabbit tick, Haemaphysalis leporispalustris, collected from an eastern cottontail in southern Manitoba; this Babesia species is a first-time discovery in Canada. This rabbit tick was also co-infected with Borrelia lanei-like spirochetes, which constitutes a first in Canada. Overall, five ticks were concurrently infected with Babesia and Bbsl pathogens and, after the molt, could potentially co-infect humans.
Notably, we provide the first authentic report of I. scapularis ticks co-infected with Bbsl and B. odocoilei 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.
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Transstadial passage is the ability of an infection to pass from one one developmental stage of an organism to another, e.g.,from the larval to the nymph stage or from the nymph to the adult: https://medical-dictionary.thefreedictionary.com/transstadial
In this report the authors confirm the transstadial passage of Bbsl in I. muris and B. odocoilei in I. scapularis (black legged deer tick).
According to the following 2000 article, Ixodes muris is also capable of transmitting Lyme disease: https://bioone.org/journals/Journal-of-Medical-Entomology/volume-37/issue-5/0022-2585-37.5.766/Vector-Competence-of-Ixodes-muris-Acari–Ixodidae-for-Borrelia/10.1603/0022-2585-37.5.766.short
Also, the following 2014 article states, “early studies revealed a higher ratio of presumed nonpathogenic B. odocolei to B. microti in areas where these species co-exist.” https://wwwnc.cdc.gov/eid/article/20/10/13-0938_article
I think it would be folly to presume anything, and the potential of B. odocoilei to be of concern to human health is relevant. In my opinion, far too much as been presumed about the ability of various ticks to transmit disease, the time it takes to transmit, as well as the ability of numerous strains of pathogens to be of human health concern.
A few things are for sure: more and more is coming out on the coinfection of ticks, that there are many strains and variations of these pathogens to be concerned with, and that current testing is abysmal in picking much of this up. These issues are some of the factors as to why people remain ill. Mainstream medicine must awaken from its coma to embrace the complexity of all of this or patients will continue to suffer.