Publications by authors named "Chelsea Himsworth"

Increased cases of Salmonella Dublin, a bacterial pathogen that primarily affects dairy cattle, have been noted in British Columbia (BC), Canada since 2015. The objective of this cross-sectional study was to 1) understand the prevalence and distribution of S. Dublin in BC dairy farms based on bulk tank milk (BTM) serology, 2) to investigate the degree of variability within percent positivity (%PP) in negative and positive farms, and 3) investigate risk factors associated with positivity.

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Hepatitis E virus (HEV) is a globally distributed pathogen that causes acute hepatitis in people. Recent human cases of HEV arising after contact with urban rats (Rattus spp.) have raised concerns regarding whether rats may be a source of HEV infection.

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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.

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Article Synopsis
  • The study investigated the connection between environmental and social factors and the presence of zoonotic pathogens like Leptospira interrogans and Bartonella spp. in Norway rats from Windsor, Ontario, highlighting public health risks due to close human-wildlife interactions.
  • Results showed that higher building density, human population density, and older buildings were linked to increased chances of Leptospira infections, while lower household income was associated with Bartonella infections in the rats.
  • The findings emphasize the importance of managing urban environments and waste, as these factors may impact the spread of diseases from rats to humans.
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Rats are an important issue in cities globally. Despite their ubiquity, perceptions and concerns about rats vary with circumstance and the context in which a person interacts with them. Municipal rat management programs are a service to communities and therefore must be responsive to the varied concerns of their residents.

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Diverse influenza A viruses (IAVs) circulate in wild birds, including highly pathogenic strains that infect poultry and humans. Consequently, surveillance of IAVs in wild birds is a cornerstone of agricultural biosecurity and pandemic preparedness. Surveillance is traditionally done by testing wild birds directly, but obtaining these specimens is labor intensive, detection rates can be low, and sampling is often biased toward certain avian species.

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Urban Norway rats (Rattus norvegicus) can carry various human pathogens, and may be involved in pathogen propagation and transmission to humans. From January 31-August 14, 2021, a community outbreak of Shigella flexneri serotype 2a occurred among unhoused or poorly housed people in the Downtown Eastside neighborhood of Vancouver, British Columbia, Canada. The source could not be identified; however, patients reported contact with rats, and previous studies indicated transmission of rat-associated zoonotic pathogens among the unhoused or poorly housed residents of this neighborhood.

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Article Synopsis
  • Researchers analyzed liver samples from 372 Norway rats in southern Ontario between 2018 and 2021 to study hepatitis E virus infections.
  • Out of those tested, 21 rats were found to be positive for the virus, indicating an infection rate of 5.6%.
  • The sequence analysis identified the infections as rat hepatitis E virus, specifically from the Rocahepevirus ratti genotype C1.
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Surveillance for SARS-CoV-2 in American mink () is a global priority because outbreaks on mink farms have potential consequences for animal and public health. Surveillance programs often focus on screening natural mortalities; however, significant knowledge gaps remain regarding sampling and testing approaches. Using 76 mink from 3 naturally infected farms in British Columbia, Canada, we compared the performance of 2 reverse-transcription real-time PCR (RT-rtPCR) targets (the envelope [] and RNA-dependent RNA polymerase [] genes) as well as serology.

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Article Synopsis
  • * Researchers used both physical trapping and camera surveillance over several months and captured 71 animals from nine species, with three domestic mink testing positive for the virus.
  • * Findings highlight the potential for transmission of SARS-CoV-2 from farmed mink to wildlife, emphasizing the effectiveness of combined trapping methods for future monitoring efforts.
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During an investigation into a cluster of Shigella flexneri serotype 2a cases in an underserved community, we assessed the relatedness of human and rat S. flexneri isolates utilizing a novel PCR targeting insertion sites (IS-PCR) of mobile elements in the Shigella genome characteristic of the cluster strain. Whole-genome sequences of S.

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Throughout the COVID-19 pandemic, numerous non-human species were shown to be susceptible to natural infection by SARS-CoV-2, including farmed American mink. Once infected, American mink can transfer the virus from mink to human and mink to mink, resulting in a high rate of viral mutation. Therefore, outbreak surveillance on American mink farms is imperative for both mink and human health.

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From 2016 to 2020, high pathogenicity avian influenza (HPAI) H5 viruses circulated in Asia, Europe, and Africa, causing waves of infections and the deaths of millions of wild and domestic birds and presenting a zoonotic risk. In late 2021, H5N1 HPAI viruses were isolated from poultry in Canada and also retrospectively from a great black-backed gull (), raising concerns that the spread of these viruses to North America was mediated by migratory wild bird populations. In February and April 2022, H5N1 HPAI viruses were isolated from a bald eagle () and broiler chickens in British Columbia, Canada.

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Background: Sequencing viruses in many specimens is hindered by excessive background material from hosts, microbiota, and environmental organisms. Consequently, enrichment of target genomic material is necessary for practical high-throughput viral genome sequencing. Hybridization probes are widely used for enrichment in many fields, but their application to viral sequencing faces a major obstacle: it is difficult to design panels of probe oligo sequences that broadly target many viral taxa due to their rapid evolution, extensive diversity, and genetic hypervariability.

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We investigated the effects of culling on Bartonella spp. bacteria carriage among urban rats in Canada. We found that the odds of Bartonella spp.

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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.

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is a zoonotic, protozoan parasite that causes potentially life-threatening diarrhea in the host and can be transmitted via the fecal-oral route. can infect cattle and may be detected in their feces using a variety of tests. We compared the level of agreement, ease of procedure, and cost among PCR, lateral flow immunoassay, fluorescent antibody, and Kinyoun acid-fast stain direct smear tests.

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Sarcocystis spp. are protozoan parasites that cause a spectrum of lesions in various hosts. Hepatic sarcocystosis and encephalitis have been described in captive American black bears (Ursus americanus) and polar bears (Ursus maritimus), and in a free-ranging grizzly bear (Ursus arctos horribilis), but have not previously been reported in free-ranging American black bears.

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From 2018 to 2019, an outbreak of rabbit hemorrhagic disease virus 2 occurred in British Columbia, Canada, in feral and domestic European rabbits (Oryctolagus cuniculus). Anthropogenic translocation of infected animals is suspected to have played a role in the introduction and spread of the virus.

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Leptospira interrogans is one of the most important zoonotic pathogens globally. In urban settings, Norway rats (Rattus norvegicus) are important reservoirs of L. interrogans, but it is unclear how this bacterium is transmitted among rats.

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Wild waterbirds are reservoir hosts for avian influenza viruses (AIV), which can cause devastating outbreaks in multiple species, making them a focus for surveillance efforts. Traditional AIV surveillance involves direct sampling of live or dead birds, but environmental substrates present an alternative sample for surveillance. Environmental sampling analyzes AIV excreted by waterbirds into the environment and complements direct bird sampling by minimizing financial, logistic, permitting, and spatial-temporal constraints associated with traditional surveillance.

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Urban Norway rats () carry several pathogens transmissible to people. However, pathogen prevalence can vary across fine spatial scales (i.e.

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Urban Norway rats () carry pathogenic spp. that are transmitted among rats and from rats to people through arthropod vectors, particularly fleas. There is marked temporospatial variation in spp.

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Urban Norway rats () are a reservoir for spp. - a genus of zoonotic bacteria transmitted by hematophagous vectors, particularly fleas. Rats and fleas may be infected with more than one species; however, mixed infections may be difficult to detect using culture and/or mono-locus PCR.

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