SARS-CoV-2 Surveillance of Wild Mice and Rats in North American Cities.

From July 2020 to June 2021, 248 wild house mice (Mus musculus), deer mice (Peromyscus maniculatus), brown rats (Rattus norvegicus), and black rats (Rattus rattus) from Texas and Washington, USA, and British Columbia, Canada, were tested for SARS-CoV-2 exposure and infection. Two brown rats and 11 house mice were positive for neutralizing antibodies using a surrogate virus neutralization test, but negative or indeterminate with the Multiplexed Fluorometric ImmunoAssay COVID-Plex, which targets full-length spike and nuclear proteins. Oro-nasopharyngeal swabs and fecal samples tested negative by RT-qPCR, with an indeterminate fecal sample in one house mouse. Continued surveillance of SARS-CoV-2 in wild rodents is warranted.

The risk of contact between visitors and Borrelia burgdorferi-infected ticks is associated with fine-scale landscape features in a southeastern Canadian nature park.

BACKGROUND: Infectious diseases are emerging across temperate regions of the world, and, for some, links have been made between landscapes and emergence dynamics. For tick-borne diseases, public parks may be important exposure sites for people living in urbanized areas of North America and Europe. In most cases, we know more about the ecological processes that determine the hazard posed by ticks as disease vectors than we do about how human population exposure varies in urban natural parks. METHODS: In this study, infrared counters were used to monitor visitor use of a public natural park in southern Quebec, Canada. A risk index representing the probability of encounters between humans and infected vectors was constructed. This was done by combining the intensity of visitor trail use and the density of infected nymphs obtained from field surveillance. Patterns of risk were examined using spatial cluster analysis. Digital forest data and park infrastructure data were then integrated using spatially explicit models to test whether encounter risk levels and its components vary with forest fragmentation indicators and proximity to park infrastructure. RESULTS: Results suggest that, even at a very fine scales, certain landscape features and infrastructure can be predictors of risk levels. Both visitors and Borrelia burgdorferi-infected ticks concentrated in areas where forest cover was dominant, so there was a positive association between forest cover and the risk index. However, there were no associations between indicators of forest fragmentation and risk levels. Some high-risk clusters contributed disproportionately to the risk distribution in the park relative to their size. There were also two high-risk periods, one in early summer coinciding with peak nymphal activity, and one in early fall when park visitation was highest. CONCLUSIONS: Here, we demonstrate the importance of integrating indicators of human behaviour visitation with tick distribution data to characterize risk patterns for tick-borne diseases in public natural areas. Indeed, understanding the environmental determinants of human-tick interactions will allow organisations to deploy more effective risk reduction interventions targeted at key locations and times, and improve the management of public health risks associated with tick-borne diseases in public spaces.

Environmental and sociodemographic factors associated with zoonotic pathogen occurrence in Norway rats (Rattus norvegicus) from Windsor, Ontario.

AIMS: Rat-associated zoonotic pathogen transmission at the human-wildlife interface is a public health concern in urban environments where Norway rats (Rattus norvegicus) thrive on abundant anthropogenic resources and live in close contact with humans and other animal species. To identify potential factors influencing zoonotic pathogen occurrence in rats, we investigated associations between environmental and sociodemographic factors and Leptospira interrogans and Bartonella spp. infections in rats from Windsor, Ontario, Canada, while controlling for the potential confounding effects of animal characteristics (i.e., sexual maturity and body condition). METHODS AND RESULTS: Between November 2018 and June 2021, 252 rats were submitted by collaborating pest control professionals. Kidney and spleen samples were collected for L. interrogans and Bartonella spp. PCR and sequencing, respectively. Of the rats tested by PCR, 12.7% (32/252) were positive for L. interrogans and 16.3% (37/227) were positive for Bartonella species. Associations between infection status and environmental and sociodemographic variables of interest were assessed via mixed multivariable logistic regression models with a random intercept for social group and fixed effects to control for sexual maturity and body condition in each model. The odds of L. interrogans infection were significantly higher in rats from areas with high building density (odds ratio [OR]: 3.76; 95% CI: 1.31-10.79; p = 0.014), high human population density (OR: 3.31; 95% CI: 1.20-9.11; p = 0.021), high proportion of buildings built in 1960 or before (OR: 11.21; 95% CI: 2.06-60.89; p = 0.005), and a moderate number of reports of uncollected garbage compared to a low number of reports (OR: 4.88; 95% CI: 1.01-23.63; p = 0.049). A negative association was observed between median household income and Bartonella spp. infection in rats (OR: 0.26; 95% CI: 0.08-0.89; p = 0.031). CONCLUSIONS: Due to the complexity of the ecology of rat-associated zoonoses, consideration of environmental and sociodemographic factors is of critical importance to better understand the nuances of host-pathogen systems and inform how urban rat surveillance and intervention efforts should be distributed within cities.

Genomic and transcriptomic characterization of delta SARS-CoV-2 infection in free-ranging white-tailed deer (Odocoileus virginianus).

White-tailed deer (WTD) are susceptible to SARS-CoV-2 and represent an important species for surveillance. Samples from WTD (n = 258) collected in November 2021 from Québec, Canada were analyzed for SARS-CoV-2 RNA. We employed viral genomics and host transcriptomics to further characterize infection and investigate host response. We detected Delta SARS-CoV-2 (B.1.617.2) in WTD from the Estrie region; sequences clustered with human sequences from October 2021 from Vermont, USA, which borders this region. Mutations in the S-gene and a deletion in ORF8 were detected. Host expression patterns in SARS-CoV-2 infected WTD were associated with the innate immune response, including signaling pathways related to anti-viral, pro- and anti-inflammatory signaling, and host damage. We found limited correlation between genes associated with innate immune response from human and WTD nasal samples, suggesting differences in responses to SARS-CoV-2 infection. Our findings provide preliminary insights into host response to SARS-CoV-2 infection in naturally infected WTD.

Widespread Exposure to Mosquitoborne California Serogroup Viruses in Caribou, Arctic Fox, Red Fox, and Polar Bears, Canada.

Northern Canada is warming at 3 times the global rate. Thus, changing diversity and distribution of vectors and pathogens is an increasing health concern. California serogroup (CSG) viruses are mosquitoborne arboviruses; wildlife reservoirs in northern ecosystems have not been identified. We detected CSG virus antibodies in 63% (95% CI 58%-67%) of caribou (n = 517), 4% (95% CI 2%-7%) of Arctic foxes (n = 297), 12% (95% CI 6%-21%) of red foxes (n = 77), and 28% (95% CI 24%-33%) of polar bears (n = 377). Sex, age, and summer temperatures were positively associated with polar bear exposure; location, year, and ecotype were associated with caribou exposure. Exposure was highest in boreal caribou and increased from baseline in polar bears after warmer summers. CSG virus exposure of wildlife is linked to climate change in northern Canada and sustained surveillance could be used to measure human health risks.

Using Serum Specimens for Real-Time PCR-Based Diagnosis of Human Granulocytic Anaplasmosis, Canada.

Whole blood is the optimal specimen for anaplasmosis diagnosis but might not be available in all cases. We PCR tested serum samples collected in Canada for Anaplasma serology and found 84.8%-95.8% sensitivity and 2.8 average cycle threshold elevation. Serum can be acceptable for detecting Anaplasma spp. when whole blood is unavailable.

The added value of One Health surveillance: data from questing ticks can provide an early signal for anaplasmosis outbreaks in animals and humans.

OBJECTIVE: In 2021, a first outbreak of anaplasmosis occurred in animals and humans in southern Québec, with 64% of confirmed human cases located in Bromont municipality. Ixodes scapularis ticks and Peromyscus mouse ear biopsies collected in Bromont from 2019 to 2021 were analyzed for Anaplasma phagocytophilum (Ap) with the objective of determining whether an early environmental signal could have been detected before the outbreak. METHODS: Samples were collected for a concurrent study aiming to reduce Lyme disease risk. Between 2019 and 2021, up to 14 experimental sites were sampled for ticks and capture of small mammals took place on three sites in 2021. Samples were screened for Ap using multiplex real-time PCR, and genetic strains were identified using a single-nucleotide polymorphism assay. RESULTS: Analyses showed an increase of 5.7% in Ap prevalence in ticks (CI95: 1.5-9.9) between 2019 and 2020, i.e., one year before the outbreak. A majority of Ap-positive ticks were infected with the zoonotic strain (68.8%; CI95: 50.0-83.9) during the study period. In 2021, 2 of 59 captured Peromycus mice were positive for Ap, for a prevalence of 3.4% (CI95: 0.4-11.7). CONCLUSION: We conclude that data collected in Bromont could have provided an early signal for an anaplasmosis risk increasing in the targeted region. This is a reminder that integrated surveillance of tick-borne diseases through structured One Health programs, i.e. systematically integrating data from humans, animals and the environment, can provide useful and timely information for better preparedness and response in public health.

RéSUMé: OBJECTIF: En 2021, suivant une éclosion d'anaplasmoses chez les animaux et les humains dans le sud du Québec, des tiques de l'espèce Ixodes scapularis et des biopsies de souris Peromyscus spp. échantillonées à Bromont, la municipalité où 64 % des cas humains confirmés était localisé, ont été testées pour Anaplasma phagocytophilum (Ap) avec pour objectif de déterminer si un signal environnemental précoce d'augmentation du risque aurait pu être détecté avant l'éclosion. MéTHODE: L'échantillonnage a été réalisé dans le cadre d'une étude visant à réduire le risque de maladie de Lyme. De 2019 à 2021, 14 sites expérimentaux ont été échantillonnés pour les tiques. En 2021, trois sites ont été sélectionnés pour la capture des micromammifères. Les échantillons ont été testés pour la présence d'Ap à l'aide d'un PCR multiplex en temps réelle et les lignées génétiques ont été identifiées grâce à un test de polymorphisme mononucléotidique. RéSULTATS: Les analyses ont montré une augmentation de 5,7 % (IC95% : 1,5­9,9) de la prévalence de Ap entre 2019 et 2020, c'est-à-dire un an avant l'éclosion. Cette augmentation est associée à la présence d'une majorité d'Ap de la lignée zoonotique (68,8 %; IC95% : 50,0­83,9) sur l'ensemble de la période étudiée. En 2021, deux Peromycus spp. capturées sur 59 étaient positives pour Ap pour une prévalence de 3,4 % (IC95% : 0,4­11,7). CONCLUSION: Les données environnementales échantillonnées à Bromont auraient pu fournir un signal précoce de l'augmentation du risque d'anaplasmose dans la région. C'est un rappel que la surveillance intégrée des maladies transmises par les tiques inspirée de l'approche Une seule santé, intégrant systématiquement des données humaines, animales et environnementales, peut fournir des informations utiles et opportunes aux autorités de santé publique.

Integrated human behavior and tick risk maps to prioritize Lyme disease interventions using a 'One Health' approach.

Lyme disease (LD) risk is emerging rapidly in Canada due to range expansion of its tick vectors, accelerated by climate change. The risk of contracting LD varies geographically due to variability in ecological characteristics that determine the hazard (the densities of infected host-seeking ticks) and vulnerability of the human population determined by their knowledge and adoption of preventive behaviors. Risk maps are commonly used to support public health decision-making on Lyme disease, but the ability of the human public to adopt preventive behaviors is rarely taken into account in their development, which represents a critical gap. The objective of this work was to improve LD risk mapping using an integrated social-behavioral and ecological approach to: (i) compute enhanced integrated risk maps for prioritization of interventions and (ii) develop a spatially-explicit assessment tool to examine the relative contribution of different risk factors. The study was carried out in the Estrie region located in southern Québec. The blacklegged tick, Ixodes scapularis, infected with the agent of LD is widespread in Estrie and as a result, regional LD incidence is the highest in the province. LD knowledge and behaviors in the population were measured in a cross-sectional health survey conducted in 2018 reaching 10,790 respondents in Estrie. These data were used to create an index for the social-behavioral component of risk in 2018. Local Empirical Bayes estimator technique were used to better quantify the spatial variance in the levels of adoption of LD preventive activities. For the ecological risk analysis, a tick abundance model was developed by integrating data from ongoing long-term tick surveillance programs from 2007 up to 2018. Social-behavioral and ecological components of the risk measures were combined to create vulnerability index maps and, with the addition of human population densities, prioritization index maps. Map predictions were validated by testing the association of high-risk areas with the current spatial distribution of human cases of LD and reported tick exposure. Our results demonstrated that social-behavioral and ecological components of LD risk have markedly different distributions within Estrie. The occurrence of human LD cases or reported tick exposure in a municipality was positively associated with tick density and the prioritization risk index (p < 0.001). This research is a second step towards a more comprehensive integrated LD risk assessment approach, examining social-behavioral risk factors that interact with ecological risk factors to influence the management of emerging tick-borne diseases, an approach that could be applied more widely to vector-borne and zoonotic diseases.

Fluralaner Baits Reduce the Infestation of Peromyscus spp. Mice (Rodentia: Cricetidae) by Ixodes scapularis (Acari: Ixodidae) Larvae and Nymphs in a Natural Environment.

The development of interventions that reduce Lyme disease incidence remains a challenge. Reservoir-targeted approaches aiming to reduce tick densities or tick infection prevalence with Borrelia burgdorferi have emerged as promising ways to reduce the density of infected ticks. Acaricides of the isoxazoline family offer high potential for reducing infestation of ticks on small mammals as they have high efficacy at killing feeding ticks for a long period. Fluralaner baits were recently demonstrated as effective, in the laboratory, at killing Ixodes scapularis larvae infesting Peromyscus mice, the main reservoir for B. burgdorferi in northeastern North America. Here, effectiveness of this approach for reducing the infestation of small mammals by immature stages of I. scapularis was tested in a natural environment. Two densities of fluralaner baits (2.1 baits/1,000 m2 and 4.4 baits/1,000 m2) were used during three years in forest plots. The number of I. scapularis larvae and nymphs per mouse from treated and control plots were compared. Fluralaner baiting reduced the number of larvae per mouse by 68% (CI95: 51-79%) at 2.1 baits/1,000 m2 and by 86% (CI95: 77-92%) at 4.4 baits/1,000 m2. The number of nymphs per mouse was reduced by 72% (CI95: 22-90%) at 4.4 baits/1,000 m2 but was not significantly reduced at 2.1 baits/1,000 m2. Reduction of Peromyscus mouse infestation by immature stages of I. scapularis supports the hypothesis that an approach targeting reservoirs of B. burgdorferi with isoxazolines has the potential to reduce tick-borne disease risk by decreasing the density of infected ticks in the environment.

Range Expansion of Ixodes scapularis and Borrelia burgdorferi in Ontario, Canada, from 2017 to 2019.

Range expansion of the vector tick species, Ixodes scapularis, has been detected in Ontario over the last two decades. This has led to elevated risk of exposure to Borrelia burgdorferi, the bacterium that causes Lyme disease. Previous research using passive surveillance data suggests that I. scapularis populations establish before the establishment of B. burgdorferi transmission cycles, with a delay of ∼5 years. The objectives of this research were to examine spatial and temporal patterns of I. scapularis and its pathogens from 2017 to 2019 in southwestern, eastern, and central Ontario, and to explore patterns of B. burgdorferi invasion. Over the 3-year study period, drag sampling was conducted at 48 sites across Ontario. I. scapularis ticks were tested for B. burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia species, including Babesia microti and Babesia odocoilei, and Powassan virus. I. scapularis was detected at 30 sites overall, 22 of which had no history of previous tick detection. B. burgdorferi was detected at nine sites, eight of which tested positive for the first time during this study and five of which had B. burgdorferi detected concurrently with initial tick detection. Tick and pathogen hotspots were identified in eastern Ontario in 2017 and 2018, respectively. These findings provide additional evidence on the range expansion and population establishment of I. scapularis in Ontario and help generate hypotheses on the invasion of B. burgdorferi in Ontario. Ongoing public health surveillance is critical to monitor changes in I. scapularis and its pathogens in Ontario.

Lyme Disease, Anaplasmosis, and Babesiosis, Atlantic Canada.

In July 2021, a PCR-confirmed case of locally acquired Babesia microti infection was reported in Atlantic Canada. Clinical features were consistent with babesiosis and resolved after treatment. In a region where Lyme disease and anaplasmosis are endemic, the occurrence of babesiosis emphasizes the need to enhance surveillance of tickborne infections.

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

Ixodes scapularis ticks are expanding their range in parts of northeastern North America, bringing with them pathogens of public health concern. While rodents like the white-footed mouse, Peromyscus leucopus, are considered the primary reservoir of many emerging tick-borne pathogens, the contribution of birds, as alternative hosts and reservoirs, to local transmission cycles has not yet been firmly established. From 2016 to 2018, we collected host-seeking ticks and examined rodent and bird hosts for ticks at 48 sites in a park where blacklegged ticks are established in Quebec, Canada, in order to characterize the distribution of pathogens in ticks and mammalian and avian hosts. We found nearly one third of captured birds (n = 849) and 70% of small mammals (n = 694) were infested with I. scapularis. Five bird and three mammal species transmitted Borrelia burgdorferi to feeding larvae (n larvae tested = 2257) and we estimated that about one fifth of the B. burgdorferi-infected questing nymphs in the park acquired their infection from birds, the remaining being attributable to mice. Ground-foraging bird species were more parasitized than other birds, and species that inhabited open habitat were more frequently infested and were more likely to transmit B. burgdorferi to larval ticks feeding upon them. Female birds were more likely to transmit infection than males, without age differentiation, whereas in mice, adult males were more likely to transmit infection than juveniles and females. We also detected Borrelia miyamotoi in larvae collected from birds, and Anaplasma phagocytophilum from a larva collected from a white-footed mouse. This study highlights the importance of characterising the reservoir potential of alternative reservoir hosts and to quantify their contribution to transmission dynamics in different species assemblages. This information is key to identifying the most effective host-targeted risk mitigation actions.

Evaluating the utility of pest control sourced rats for zoonotic pathogen surveillance.

Norway rats (Rattus norvegicus) inhabit cities worldwide and live in close association with humans. Studies of urban rat zoonoses often rely on live-trapping, with fewer studies using rats sourced through lethal pest control interventions. Our objectives were to evaluate the utility of rats collected by pest control professionals for zoonotic pathogen surveillance and determine whether we could detect Leptospira interrogans and Streptobacillus moniliformis in pest control sourced rats. Rat carcasses were submitted from Windsor, Canada by pest control professionals between November 2018 and March 2020. Submissions were categorized by season and land use. Necropsies were performed to classify carcass quality, collect tissue samples, and record demographic data. The association between carcass quality and the ability to collect tissue samples for pathogen surveillance was assessed via an exact logistic regression model. Using PCR, a subset of kidney and spleen samples were tested for L. interrogans and S. moniliformis, respectively. Our sample of pest control sourced rats had similar sex and age distributions to those of live-trapping studies. Rats were primarily submitted from residential and industrial locations during fall, winter, and spring, which may reflect pest control service areas and peak business periods, rather than rat distribution. Of 124 submissions, 98 (79.0%) of rats showed only mild decomposition. The odds of collecting all tissue samples were reduced for fair compared to good-quality carcasses (OR: 0.029; 95% CI: 0-0.25; p = .0009) and for poor compared to fair-quality carcasses (OR: 0.048; 95% CI: 0.00085-0.53; p = .0065). Leptospira interrogans and S. moniliformis were detected in 9.1% (4/44) and 27.3% (15/55) of a subset of rats tested, respectively. Our results suggest that pest control sourced rats are suitable for surveillance for multiple zoonotic pathogens in urban environments. This method of rat collection may provide preliminary information to guide more detailed ecological studies.

Epidemiology of ticks submitted from human hosts in Alberta, Canada (2000-2019).

ABSTRACTThe geographic range and occurrence of tick species is dynamic. This has important public health implications due to important tick species that can transmit pathogens. This study presents a retrospective review of tick genera recovered from humans and submitted for identification in Alberta, Canada, over a 19-year period. The total number of ticks and proportion of genera were analyzed over time. Molecular testing for a number of pathogens associated with Ixodes scapularis and I. pacificus was conducted. A total of 2,358 ticks were submitted between 2000 and 2019, with 98.6% being acquired in Alberta. The number of ticks submitted increased significantly over time (p < 0.0001). Dermacentor ticks were the most abundant genus, followed by Ixodes and Amblyomma. There was a significant decrease in the proportion of Dermacentor ticks between 2013 and 2019 (p = 0.02), with a corresponding increase in the proportion of Ixodes ticks over the same time (p = 0.04). No statistically significant change in seasonality was identified. Borrelia burgdorferi was detected in 8/76 (10.5%; 95% CI 5.4-19.4%) of all I. scapularis and I. pacificus ticks submitted. This translated to a B. burgdorferi positivity of 0.35% (95% CI 0.15-0.68%) among all ticks received. Dermacentor species (especially D. andersoni) remains the most common tick feeding on humans in Alberta. Small numbers of vector species (including I. scapularis/pacificus) are encountered annually over widely separated geographic areas in the province. The risk of exposure to tick-borne pathogens (e.g. Lyme disease) in Alberta remains low.

Fine-scale determinants of the spatiotemporal distribution of Ixodes scapularis in Quebec (Canada).

The tick vector of Lyme disease, Ixodes scapularis, is currently expanding its geographical distribution northward into southern Canada driving emergence of Lyme disease in the region. Despite large-scale studies that attributed different factors such as climate change and changes in land use to the geographical expansion of the tick, a comprehensive understanding of local patterns of tick abundance is still lacking in that region. Using a newly endemic periurban nature park located in Quebec (Canada) as a model, we explored intra-habitat patterns in tick distribution and their relationship with biotic and abiotic factors. We verified the hypotheses that (1) there is spatial heterogeneity in tick densities at the scale of the park and (2) these patterns can be explained by host availability, habitat characteristics and microclimatic conditions. During tick activity season in three consecutive years, tick, deer, rodent and bird abundance, as well as habitat characteristics and microclimatic conditions, were estimated at thirty-two sites. Patterns of tick distribution and abundance were investigated by spatial analysis. Generalised additive mixed models were constructed for each developmental stage of the tick and the relative importance of significant drivers on tick abundance were derived from final models. We found fine-scale spatial heterogeneity in densities of all tick stages across the park, with interannual variability in the location of hotspots. For all stages, the local density was related to the density of the previous stage in the previous season, in keeping with the tick's life cycle. Adult tick density was highest where drainage was moderate (neither waterlogged nor dry). Microclimatic conditions influenced the densities of immature ticks, through the effects of weather at the time of tick sampling (ambient temperature and relative humidity) and of the seasonal microclimate at the site level (degree-days and number of tick adverse moisture events). Seasonal phenology patterns were generally consistent with expected curves for the region, with exceptions in some years that may be attributable to founder events. This study highlights fine scale patterns of tick population dynamics thus providing fundamental knowledge in Lyme disease ecology and information applicable to the development of well-targeted prevention and control strategies for public natural areas affected by this growing problem in southern Canada.

Babesia microti in a Canadian blood donor and lookback in a red blood cell recipient.

BACKGROUND AND OBJECTIVES: We describe the third documented case of autochthonous human babesiosis in Canada and the second in a Canadian blood donor. MATERIALS AND METHODS: Multiple laboratory investigations were carried out on the donor and the immunocompromised recipient of an associated, potentially infectious red blood cell product. RESULTS: The donor had not travelled except for outdoor exposure in south-eastern Manitoba, followed by illness and hospital admission. The donor had a notable parasitaemia, positive for Babesia microti using whole blood nucleic acid testing (NAT). The recipient was negative for B. microti by both serology and NAT. CONCLUSION: There was no evidence of transfusion-transmitted babesiosis.

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

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.

SARS-CoV-2 wildlife surveillance in Ontario and Québec.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the coronavirus disease 2019 pandemic, is capable of infecting a variety of wildlife species. Wildlife living in close contact with humans are at an increased risk of SARS-CoV-2 exposure and, if infected, have the potential to become a reservoir for the pathogen, making control and management more difficult. The objective of this study is to conduct SARS-CoV-2 surveillance in urban wildlife from Ontario and Québec, increasing our knowledge of the epidemiology of the virus and our chances of detecting spillover from humans into wildlife. Methods: Using a One Health approach, we leveraged activities of existing research, surveillance and rehabilitation programs among multiple agencies to collect samples from 776 animals from 17 different wildlife species between June 2020 and May 2021. Samples from all animals were tested for the presence of SARS-CoV-2 viral ribonucleic acid, and a subset of samples from 219 animals across three species (raccoons, Procyon lotor; striped skunks, Mephitis mephitis; and mink, Neovison vison) were also tested for the presence of neutralizing antibodies. Results: No evidence of SARS-CoV-2 viral ribonucleic acid or neutralizing antibodies was detected in any of the tested samples. Conclusion: Although we were unable to identify positive SARS-CoV-2 cases in wildlife, continued research and surveillance activities are critical to better understand the rapidly changing landscape of susceptible animal species. Collaboration between academic, public and animal health sectors should include experts from relevant fields to build coordinated surveillance and response capacity.

SARS-CoV-2 wildlife surveillance surrounding mink farms in British Columbia, Canada.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect many wild and domestic animal species. Farmed American mink (Neovison vison) are particularly susceptible to infection. Outbreaks of SARS-CoV-2 were detected in farmed mink on three mink farms in British Columbia (BC), Canada between December 2020 and May 2021. In BC, mink farm density and proximity to wildlife habitats increase transmission risks from infected farmed mink. The objective of this study is to investigate the risk of SARS-CoV-2 spreading to and from wildlife in the area surrounding infected mink farms in BC, Canada, as well as to compare the effectiveness of physical and camera trapping surveillance methodologies. Methods: A combination of physical and camera trapping was used on and around three BC mink farms with active SARS-CoV-2 infections between January 22, 2021, and July 10, 2021. Samples from trapped animals, including escaped farmed mink, were tested for SARS-CoV-2. Camera images from one mink farm were reviewed to determine species and proximity to the mink barn. Results: Seventy-one animals of nine species were captured and sampled. Three captured mink tested positive for SARS-CoV-2 by polymerase chain reaction and serology; the remaining samples were negative for SARS-CoV-2. Genotyping of the three positive mink indicated these were domestic (vs. wild) mink. A total of 440 animals of 16 species were photographed at the one farm where cameras were deployed. Conclusion: Detection of SARS-CoV-2 in escaped farmed mink is concerning and demonstrates the potential for transmission from farmed mink to wildlife, particularly given the observation of wildlife known to be susceptible to SARS-CoV-2 near infected mink farms. Combined use of physical and camera trapping contributed to the breadth of the results and is strongly recommended for future surveillance.

Evaluation of commercial SARS-CoV-2 serological assays in Canadian public health laboratories.

The COVID-19 pandemic has led to the influx of immunoassays for the detection of antibodies towards severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the global market. The Canadian Public Health Laboratory Network Serology Task Force undertook a nationwide evaluation of twelve laboratory and 6 point-of-care based commercial serological assays for the detection of SARS-CoV-2 antibodies. We determined that there was considerable variability in the performance of individual tests and that an orthogonal testing algorithm should be prioritized to maximize the accuracy and comparability of results across the country. The manual enzyme immunoassays and point-of-care tests evaluated had lower specificity and increased coefficients of variation compared to automated enzyme immunoassays platforms putting into question their utility for large-scale sero-surveillance. Overall, the data presented here provide a comprehensive approach for applying accurate serological assays for longitudinal sero-surveillance and vaccine trials while informing Canadian public health policy.