April Research Round Up

Transmission patterns of tick-borne pathogens among birds and rodents in a forested park in southeastern Canada

Between 2016 and 2018, Quebec researchers collected close to 30,000 blacklegged ticks (Ixodes scapularis), roughly 850 birds of 50 different species, more than 650 white-footed mice (Peromyscus leucopus), a dozen Eastern chipmunks (Tamias striatus), an equal number of northern short-tailed shrews (Blarina brevicauda), and one Red-backed vole (Myodes gapperi) from the lush forests of Mont Saint-Bruno National Park (located roughly 30KM east of Montreal) and found that while white-footed mice were most likely responsible for passing on Lyme disease bacteria (Borrelia burgdorferi) to the greatest number of blacklegged tick nymphs, birds were likely responsible for infecting one-fifth of blacklegged tick nymphs. These researchers also detected the human pathogens Borrelia miyamotoi, and Anaplasma phagocytophilum in the park.

Spatiotemporal trends and socioecological factors associated with Lyme disease in eastern Ontario, Canada from 2010-2017

These researchers analyzed data relating to human Lyme disease cases and passive tick surveillance from four eastern Ontario health units (encompassing the communities of Brockville, Carleton Place, Cornwall, Gananoque, Kingston, Ottawa, Perth and surrounding rural areas) between 2010 and 2017. They found that, with the exception of Ottawa, most Lyme disease infections were acquired in the immediate vicinity of patients' homes. For Ottawa residents, cottages and locations where they engaged in recreational activities, school or work joined home turf as the most popular places to acquire Lyme disease. Researchers also found that locations where higher numbers of Lyme disease cases were recorded correlated to larger numbers of Lyme-infected blacklegged ticks being submitted to health units. Hotspots associated with higher risk included the region stretching from Gananoque to Brockville. Mixed forests and rural settings also equated to higher risk while urbanized environments and neighbourhoods with more "walkable" areas were associated with lower risk.

Improving Widescale Monitoring of Ectoparasite Presence in Northern Canadian Wildlife with the Aid of Citizen Science

In 2018, researchers from the University of Toronto and the Yukon Government's Animal Health Unit established a three-year citizen science program in the Yukon that saw hunters gathering samples from vulnerable moose and caribou populations in an effort to better monitor winter tick (Dermacentor albipictus) infestations in the territory. Through social media engagement, incentives, printed material and standardized sampling kits, participants were encouraged to submit hide samples along with completed collection information. The result was a 100-fold increase in submissions that helped researchers to expand their surveillance efforts hundreds of kilometres further north, identify unique winter tick populations, establish baselines for future research, and define priority areas . No ticks other than winter ticks were identified in the Yukon during the course of this study.

Canadian blood suppliers: An expanding role in public health surveillance?

Basically, the authors of this paper advocate for the increased role of Canada's two primary blood services agencies, Hema-Quebec and Canada Blood Services, in public health surveillance. Because of the way these arms-length agencies operate, they can potentially play a critical role in the monitoring of an increasing number of human pathogens through screening blood donations and sharing that data with researchers. There have been several studies in recent years in which blood agency data has been used to help public health professionals get an indication of prevalence amongst the donating public for several pathogens, including the tick-borne virus Babesia microti. Part of the appeal of this kind of using these blood agencies in this way is that Hema-Quebec and Canada Blood Services receive donations from across the breadth of Canada from ostensibly healthy citizens mostly between the ages of 17 and 72, which would give them a large sample demographic. They also collect blood almost every single day, screen that blood for specific pathogens, and collect data through questionnaires that can be keyed to each sample. All of this allows public health professionals to track disease that can be asymptomatic, including several of the tick-borne illnesses.

Behavioural risk factors associated with reported tick exposure in a Lyme disease high incidence region in Canada

Recruiting more than 10,000 randomly selected residents of the Estrie region of Quebec between June and September 2018, researchers used a questionnaire in an effort to determine if there was a connection between human behaviour and tick exposure in this high Lyme risk region. This study found that only roughly a quarter of people they surveyed did tick checks, a third used tick repellants, and just under half showered after outdoor activities. Not only were the rates at which residents engaged in preventative behaviour low, they were stubbornly so, remaining inline with those recorded a various points over the past decade. This lack of behaviour modification has led these researchers to conclude that there has been no progress in getting people to change their behaviour in response to increased Lyme disease risk in recent years. Their recommendation is for public education about ticks and tick-borne diseases increase in the coming years in an effort to get more residents in high risk areas to adopt preventative measures.