Journal of Wildlife Diseases最新文献

Great Crested Flycatchers (Myiarchus crinitus), migratory passerines with a breeding range throughout the northeastern, midwestern, and southern US, are banded annually at the Braddock Bay Bird Observatory located on the southern shore of Lake Ontario, New York, USA. In 2016, a Great Crested Flycatcher was observed with distinct lesions in the gular and ventral neck region, which prompted evaluation for similar lesions in subsequently trapped flycatchers and other passerine species. From 2016 to 2023, 62/102 banded Great Crested Flycatchers had their gular region examined, and seven were found to have lesions (11.3% incidence). Similar lesions were not found in any other species. Lesions were localized to the gular region and included extensive feather loss with thickened, corrugated, pale-yellow skin. Grossly visible 1- to 2-mm-diameter, raised, white-to-yellow foci throughout the affected region corresponded microscopically to feather follicles that were massively dilated with mites. Morphologic analysis of mites obtained from skin scrapes revealed that this mite species belongs to the family Harpirhynchidae. Mites in this family have restricted avian host ranges and cause varying clinical presentations in passerines, though many species remain unidentified. PCR efforts were unsuccessful in yielding a species-level identification. Further monitoring of Great Crested Flycatchers and other avian species is warranted, as the fitness implications of this ectoparasitism at the individual and population levels are not known.

A subadult Brown Pelican (Pelecanus occidentalis) was found dead near a fishing pier in Florida, USA. Necropsy revealed abundant sand accumulation throughout the intestines. Fibrinous coelomitis with isolation of mixed bacteria, including Enterobacter cloacae complex, suggests secondary intestinal compromise. Sand ingestion might reflect geophagia, environmental hardships, or age-related diving inexperience.

After detecting chronic wasting disease (CWD) in white-tailed deer (Odocoileus virginianus) in Hampshire County, West Virginia, USA, in 2005, we investigated the change of CWD apparent prevalence and potential factors influencing infection risk during the invasion front. Over eight sampling years (2006-2012 and 2017) during a 12-yr period within a 101-km2-area monitoring zone, we sampled and tested a total of 853 deer for CWD by ELISA and immunohistochemistry. Bayesian logistic regression of risk factors included collection year, age class, sex, and adjusted body weight (weight after accounting for sex, age, kidney fat index, and number of fetuses). In the whole-herd model (n=634), collection year, age, and adjusted body weight were associated with increased odds of CWD, whereas an age-weight interaction had a negative relationship. We found that males drove the positive associations with age and adjusted body weight, whereas females were responsible for the negative interaction effect. These findings suggest potential behavioral and physiological mechanisms related to sex that may influence CWD exposure. Older males exhibited higher CWD prevalence, aligning with previous studies. Notably, the novel finding of adjusted body weight as a risk factor in males warrants further investigation, and this study highlights the need for future research on social behavior and its role in CWD transmission within white-tailed deer populations.

Vesicular stomatitis virus (VSV) outbreaks periodically occur in livestock in the western US and are thought to originate from outside this country. Feral swine (Sus scrofa) have been identified as an amplifying host for vesicular stomatitis New Jersey virus (VSNJV) and have been used to better understand the epidemiology of this virus through serosurveillance. This study aimed to determine if antibodies to vesicular stomatitis Indiana virus (VSIV) and VSNJV were present in feral swine in the western US and to determine if seropositive animals were associated with areas of previously detected VSV in livestock. A total of 4,541 feral swine samples was tested using virus neutralization (VN); samples exhibiting neutralizing activity against one or more of the viruses were confirmed using competitive ELISA (cELISA). Eight sera exhibited neutralizing activity by VN assay and a single serum sample from an animal from Kinney County, Texas sampled in December 2019 tested positive for antibodies to VSIV by cELISA. This finding is supported by a local outbreak of VSIV in horses in the same county in June 2019. The low prevalence of antibodies against VSNJV and VSIV was unexpected but indicates that feral swine in the western US do not represent an endemic reservoir for either of these viruses.

Sarcoptes scabiei mites and skin lesions consistent with severe sarcoptic mange were identified in a Tasmanian devil (Sarcophilus harrisii) and Bennett's wallaby (Notamacropus rufogriseus) from Tasmania, Australia. The devil and wallaby both had severe hyperkeratotic skin lesions. All stages of mite development were identified in the devil, suggesting parasite reproduction on the host. The devil was also affected by devil facial tumor disease and several other parasites. This expands the global host range of species susceptible to this panzootic mange disease.

Serpentoviruses are strongly associated with upper respiratory tract disease in captive and free-ranging bluetongued skinks (Tiliqua spp.). In Australia, bluetongue serpentoviruses were first reported in shingleback skinks (Tiliqua rugosa) with upper respiratory tract disease that presented to wildlife rehabilitation facilities in Perth, Western Australia. Since then, serpentoviruses have been detected commonly in captive bluetongued skinks from most areas of Australia, yet knowledge about the prevalence and distribution of these viruses in free-ranging bluetongued skinks, and other skink species, remains limited. Oral swabs were collected from 162 shingleback skinks from four areas in Western Australia and neighboring South Australia to screen for bluetongue serpentoviruses by PCR. The proportions of PCR positives were 0% (0/4) for Rottnest Island (a small island west of Perth, Western Australia), 3% (1/32) for the Shire of Kent (∼5,600 km2 in the southwest of Western Australia), 1% (1/91) from an approximately 250,000 km2 area across South Australia and Western Australia, and 0% (0/35) from Mount Mary (∼150 km2 in the mid north of South Australia). Neither of the two PCR-positive shingleback skinks had overt signs of upper respiratory tract disease. These results are consistent with serpentoviruses occurring at a relatively low crude prevalence of 1.4% (95% confidence interval, 0.2-4.9%) across these areas, although the potential bias from sampling active and apparently healthy individuals may mean that this estimate is lower than the true prevalence. This contrasts with the high proportion of PCR positives reported in captive individuals. In the absence of experimental or observational data on viral clearance and recovery, Tiliqua spp. skinks that are intended for release into the wild should be housed with strict biosecurity to prevent interactions with captive individuals and screened to ensure that they are not PCR positive before release.

A juvenile coyote (Canis latrans) was presented to a wildlife rehabilitation center with intermittent circling, hypernatremia, and elevated blood urea nitrogen. Diagnostic testing supported a diagnosis of hypodipsic hypernatremia. Postmortem magnetic resonance imaging (MRI) and necropsy revealed marked hypoplasia of the corpus callosum, a finding not previously reported in a free-ranging animal.

It has been proposed that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that spread through human populations as a pandemic originated in Asian bats. There is concern that infected humans could transmit the virus to native North American bats; therefore, the susceptibility of several North American bat species to the pandemic virus has been experimentally assessed. Big brown bats (Eptesicus fuscus) were shown to be resistant to infection by SARS-CoV-2, whereas Mexican free-tailed bats (Tadarida brasiliensis) became infected and orally excreted moderate amounts of virus for up to 18 d postinoculation. Little brown bats (Myotis lucifugus) frequently contact humans, and their populations are threatened over much of their range due to white-nose syndrome, a fungal disease that is continuing to spread across North America. We experimentally challenged little brown bats with SARS-CoV-2 to determine their susceptibility and host potential and whether the virus presents an additional risk to this species. We found that this species was resistant to infection by SARS-CoV-2. These findings provide reassurance to wildlife rehabilitators, biologists, conservation scientists, and the public at large who are concerned with possible transmission of this virus to threatened bat populations.

Contagious ecthyma is a common, worldwide, and highly transmissible viral zoonotic skin disease caused by the orf virus (ORFV). It mainly affects farmed small ruminants, but it has also been described in a broad range of wild and domestic mammals, with Caprinae species most susceptible. Between November 2019 and January 2020, adults, juveniles, yearlings, and kids from an Iberian ibex (Capra pyrenaica) population established in the Montgrí Massif Natural Park (Catalonia, northeastern Spain) were observed with clinical signs and lesions compatible with ORFV infection. The carcass of an adult male with severe disease enabled sample collection for histopathology and molecular studies, confirming ORFV DNA in the skin lesions. Sequence analyses indicated that the ORFV strain detected had high homology (>98%) with strains previously obtained from other European wild ruminant species. The outbreak peaked in December 2019, with an estimated prevalence of 68.97% (95% confidence interval, 53.35-84.59). From February 2020 forward, no individuals with lesions were observed. The yearly counts for population monitoring corroborated the apparently negligible ORFV impact on the ibex population of the Montgrí Natural Park. There are no previous reports of contagious ecthyma in a free-ranging Iberian ibex population.

Susceptibility of free-ranging US wildlife to SARS-CoV-2 infection has been documented. Nasal or oral swabs and blood from 337 wild mammals (31 species) in Arizona USA, tested for antibodies and by reverse-transcription PCR, did not reveal evidence of SARS-CoV-2. Broader surveillance efforts are necessary to understand the role of wildlife.