Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2019

Abstract

Background The primary vectors of the agent of Lyme disease in Canada are Ixodes scapularis and Ixodes pacificus ticks. Surveillance for ticks and the pathogens they can transmit can inform local tick-borne disease risk and guide public health interventions. The objective of this article is to characterize passive and active surveillance of the main Lyme disease tick vectors in Canada in 2019 and the tick-borne pathogens they carry. Methods Passive surveillance data were compiled from the National Microbiology Laboratory Branch and provincial public health data sources. Active surveillance was conducted in selected sentinel sites in all provinces. Descriptive analysis of ticks submitted and infection prevalence of tick-borne pathogens are presented. Seasonal and spatial trends are also described. Results In passive surveillance, specimens of I. scapularis (n=9,858) were submitted from all provinces except British Columbia and I. pacificus (n=691) were submitted in British Columbia and Alberta. No ticks were submitted from the territories. The seasonal distribution pattern was bimodal for I. scapularis adults, but unimodal for I. pacificus adults. Borrelia burgdorferi was the most prevalent pathogen in I. scapularis (18.8%) and I. pacificus (0.3%). In active surveillance, B. burgdorferi was identified in 26.2% of I. scapularis ; Anaplasma phagocytophilum in 3.4% of I. scapularis , and Borrelia miyamotoi and Powassan virus in 0.5% or fewer of I. scapularis . These same tick-borne pathogens were not found in the small number of I. pacificus tested. Conclusion This surveillance article provides a snapshot of the main Lyme disease vectors in Canada and their associated pathogens, which can be used to monitor emerging risk areas for exposure to tick-borne pathogens.

Anaplasmose granulocytaire humaine compliquée d’un syndrome hémophagocytaire et d’une coinfection

“…Ixodes scapularis est aussi un vecteur de plusieurs autres agents pathogènes, notamment Anaplasma phagocytophilum , Borrelia miyamotoi , Ehrlichia muris eauclairensi s, Babesia microti , Babesia duncani et le virus Powassan. Anaplasma phagocytophilum , B. miyamotoi et B. duncani sont répandus au Canada 4 , 5 . Babesia microti demeure limité aux provinces de l’Est 2 .…”

“…Le nombre de tiques hébergeant plus d’un agent pathogène est en hausse, mais le phénomène est encore rare, observé chez moins de 1 % des tiques examinées 4 . La coinfection par plusieurs agents pathogènes transmis par des tiques demeure possible, soit par la morsure d’une seule tique ou, plus probablement, par la morsure de plusieurs tiques hébergeant différents agents pathogènes.…”

Human granulocytic anaplasmosis complicated by hemophagocytic syndrome and coinfection

“…Anaplasma phagocytophilum, B. miyamotoi and B. duncani are widespread within Canada. 4,5 Babesia microti remains restricted to the eastern provinces. 2 Powassan virus is very uncommon, with only 39 clinical cases documented in the US in 2019.…”

“…6 The presence of more than 1 pathogen harboured by a single tick is increasingly observed but remains uncommon, occurring in less than 1% of surveyed ticks. 4 Coinfection by multiple tickborne pathogens remains possible either through inoculation by a single tick or (more likely) via multiple ticks harbouring different pathogens.…”

Historical associations and spatiotemporal changes of pathogen presence in ticks in Canada: A systematic review

“…By the 2010s, I. scapularis ticks with B. burgdorferi were established in Manitoba, Ontario, Quebec, New Brunswick, and Nova Scotia (Ogden et al, 2014). Today, I. scapularis ticks are widely distributed across southern Canada (Guillot et al, 2020;Wilson et al, 2022). This tick vector is of growing public health concerns due to its ability to transmit multiple tick-borne pathogens, including Anaplasma phagocytophilum, Babesia species, Borrelia species, Ehrlichia species, and Powassan virus (Table 1; Dibernardo et al, 2014;Nelder et al, 2021;Wilson et al, 2022).…”