Rapid Antigen-Capture Assay To Detect West Nile Virus in Dead Corvids

The utility of the VecTest antigen-capture assay to detect West Nile virus (WNV) in field-collected dead corvids was evaluated in Manitoba and Ontario, Canada, in 2001 and 2002. Swabs were taken from the oropharynx, cloaca, or both of 109 American Crows, 31 Blue Jays, 6 Common Ravens, and 4 Black-billed Magpies from Manitoba, and 255 American Crows and 28 Blue Jays from Ontario. The sensitivity and specificity of the antigen-capture assay were greatest for samples from American Crows; oropharyngeal swabs were more sensitive than cloacal swabs, and interlaboratory variation in the results was minimal. The sensitivity and specificity of the VecTest using oropharyngeal swabs from crows were 83.9% and 93.6%, respectively, for Manitoba samples and 83.3% and 95.8%, respectively, for Ontario birds. The VecTest antigen-capture assay on oropharyngeal secretions from crows is a reliable and rapid diagnostic test that appears suitable for incorporation into a WNV surveillance program

The First case of Locally Acquired Tick-Borne Babesia Microti

A child with a complicated medical history that included asplenia acquired an infection with Babesia microti in the summer of 2013 and had not travelled outside of Manitoba. Although the clinical findings were subtle, astute laboratory work helped to reach a preliminary identification of Babesia species, while reference laboratory testing confirmed the diagnosis. Blacklegged ticks (Ixodes scapularis) are known to transmit Borrelia burgdorferi and Anaplasma phagocytophilum in the province; however, the present case represents the first known instance of tick-borne B microti, both in Manitoba and in Canada. The expanding territory of the blacklegged tick increases the relevance of this emerging infection. Clinicians, laboratory medical practitioners and public health officials should be aware of B microti as a potential locally acquired infection in Canada

Mapping clusters of chikungunya and dengue transmission in northern Tanzania using disease exposure and vector data

Background: Dengue and chikungunya are mosquito-borne viral diseases that are of public health importance throughout the tropical and subtropical regions of the world. Seasonal variations in transmission of these viruses have been suggested owing to the ecology of their mosquito vectors. However, little is known about the epidemiology of the diseases Tanzania. To address this gap, seasonal community-based cross-sectional surveys were undertaken to identify potential clusters of transmission in Hai district in northern Tanzania.Methods: Epidemiological and entomological data from two cross-sectional surveys were used to examine the spatial pattern of dengue and chikungunya transmission. Six villages namely, Boma Ng’ombe, Magadini, Rundugai, Nshara and Kware were involved in the study. Serological measures of dengue and chikungunya virus infections were derived using enzyme-linked immunosorbent assays, and all participants were geo-referenced to the household level using a global positioning system. Potential clusters of individual exposed to dengue and chikungunya virus , as well as clusters of Aedes mosquitoes in the wet and dry seasons were detected using SaTScan. All significant clusters (with p≤0.05) were mapped using ArcGIS.Results: A large, widely dispersed cluster of chikungunya exposed individuals was detected spanning Rundugai and parts of Magadini villages (RR = 2.58,  p= 0.01), while no significant clustering was observed in the dry season. Spatial clusters of Aedes aegypti were detected in Rundugai in both the wet and dry seasons (RR = 2.56, p< 0.001 and RR = 2.24, p=0.05, respectively). In the dry season a small cluster was also detected in Kware (RR = 2.25, p=0.05). No significant clusters of dengue were detected in both seasons.Conclusion: Clusters of chikungunya-exposed individuals and Aedes mosquitoes indicate on-going transmission of chikungunya virus in Hai district of northern Tanzania

West Nile Virus Outbreak in North American Owls, Ontario, 2002

Susceptibility of North American owls to WNV is associated with native breeding range

Whole genome sequencing and phylogenetic analysis of strains of the agent of Lyme disease Borrelia burgdorferi from Canadian emergence zones

Lyme disease is emerging in southern Canada due to range expansion of the tick vector, followed by invasion of the agent of Lyme disease Borrelia burgdorferi sensu stricto. Strain diversity, as determined by Multi Locus Sequence Typing, occurs in this zone of emergence, and this may have its origins in adaptation to ecological niches, and have phenotypic consequences for pathogenicity and serological test performance. Sixty-four unique strains were cultured from ticks collected in southern Canada and the genomes sequenced using the Illumina MiSeq platform. A maximum likelihood phylogenetic tree of the chromosome revealed two large clades with multiple subclades. Consistent with previous studies on this species, the clades were not geographically defined, and some Canadian strains were highly divergent from previously sequenced US strains. There was evidence for recombination in the chromosome but this did not affect the phylogeny. Analysis of chromosomal genes indicated that these are under intense purifying selection. Phylogenies of the accessory genome and chromosome were congruent. Therefore strain differences identified in the phylogeny of chromosomal genes likely act as a proxy for genetic determinants of phenotypic differences amongst strains that are harboured in the accessory genome. Further studies on health implications of strain diversity are needed

Two Anaplasma phagocytophilum Strains in Ixodes scapularis Ticks, Canada

We developed PCR-based assays to distinguish a human pathogenic strain of Anaplasma phagocytophilum, Ap-ha, from Ap-variant 1, a strain not associated with human infection. The assays were validated on A. phagocytophilum-infected blacklegged ticks (Ixodes scapularis) collected in Canada. The relative prevalence of these 2 strains in I. scapularis ticks differed among geographic regions

Locally Acquired Leptospirosis in Expedition Racer, Manitoba, Canada

Leptospirosis is found worldwide, except in northern regions. We report a case associated with a backcountry adventure race in Manitoba, Canada. Initially, nonspecific symptomatology and diagnostic pitfalls contributed to a delay in identification. Careful attention needs to be paid to exposure to and risk for leptospirosis in northern and temperate climates

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

Monitoring the patterns of submission and presence of tick-borne pathogens in Ixodes scapularis collected from humans and companion animals in Ontario, Canada (2011–2017)

Abstract Background The universal nature of the human–companion animal relationship and their shared ticks and tick-borne pathogens offers an opportunity for improving public and veterinary health surveillance. With this in mind, we describe the spatiotemporal trends for blacklegged tick (Ixodes scapularis) submissions from humans and companion animals in Ontario, along with pathogen prevalence. Methods We tested tick samples submitted through passive surveillance (2011–2017) from humans and companion animals for Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum and Babesia microti. We describe pathogen prevalence in ticks from humans and from companion animals and constructed univariable Poisson and negative binomial regression models to explore the spatiotemporal relationship between the rates of tick submissions by host type. Results During the study, there were 17,230 blacklegged tick samples submitted from humans and 4375 from companion animals. Tick submission rates from companion animals were higher than expected in several public health units (PHUs) lacking established tick populations, potentially indicating newly emerging populations. Pathogen prevalence in ticks was higher in PHUs where established blacklegged tick populations exist. Borrelia burgdorferi prevalence was higher in ticks collected from humans (maximum likelihood estimate, MLE = 17.5%; 95% confidence interval, CI 16.97–18.09%) than from companion animals (9.9%, 95% CI 9.15–10.78%). There was no difference in pathogen prevalence in ticks by host type for the remaining pathogens, which were found in less than 1% of tested ticks. The most common co-infection B. burgdorferi + B. miyamotoi occurred in 0.11% of blacklegged ticks from humans and animals combined. Borrelia burgdorferi prevalence was higher in unengorged (21.9%, 95% CI 21.12–22.65%) than engorged ticks (10.0%, 95% CI 9.45–10.56%). There were no consistent and significant spatiotemporal relationships detected via regression models between the annual rates of submission of each host type. Conclusions While B. burgdorferi has been present in blacklegged ticks in Ontario for several decades, other tick-borne pathogens are also present at low prevalence. Blacklegged tick and pathogen surveillance data can be used to monitor risk in human and companion animal populations, and efforts are under consideration to unite surveillance efforts for the different target populations. Graphic Abstrac