Journal of Wildlife Diseases最新文献

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.

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.

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.

Monitoring wildlife health is essential for understanding global disease patterns, particularly as vector-borne infections extend the geographic ranges and thereby hosts due to environmental shifts. Anaplasma marginale, primarily impacting cattle, has economic implications and has been found in diverse hosts, yet its presence in capybaras (Hydrochoerus hydrochaeris), influential in tick-borne pathogen spread, lacks comprehensive understanding. From 2015 to 2022, 14 capybaras were surveyed across two different areas of northeastern Argentina. In 1 of 14 (7%) capybaras, the presence of A. marginale was confirmed through the amplification of specific genes, msp5 and msp1β. In addition, A. marginale DNA was detected in the capybara's blood sample through quantitative PCR, with a cycle threshold value of 30.81 (800 copies per reaction). Amplification of a fragment of the msp1α gene revealed PCR products of three different sizes, suggesting the presence of at least three coinfecting A. marginale variants in the capybara host. This study suggests that capybaras are wild hosts for A. marginale in the Ibera Wetlands in Argentina, potentially influencing the infection dynamics of both domestic and wild species. This finding highlights the necessity for thorough studies on the role of capybaras in disease dynamics, crucial for understanding wildlife health and the spread of disease.

Invasive species threaten wildlife. We detected invasive ticks on wildlife and indigenous ticks on invasive mammals in southern Brazil. The invasive cattle tick Rhipicephalus microplus was found on 12 native mammals and one invasive exotic (Axis axis). The Neotropical tick Amblyomma dubitatum was found on three invasive alien mammal species.

Soft ticks in the genus Ornithodoros occur throughout the Mojave Desert in southern Nevada, southeastern California, and parts of southwestern Utah and northwestern Arizona, USA, and are frequently observed parasitizing Mojave desert tortoises (Gopherus agassizii). However, limited research exists examining the relationship between ticks and desert tortoises. Mojave desert tortoises are listed as threatened by the US Fish and Wildlife Service, and as such, their populations are monitored and individual tortoise health is routinely assessed. These health assessments document the presence and abundance of ticks present on tortoises, but detailed examination of the relationship between ticks and tortoise health has been lacking. This study analyzed the relationship between tick presence and desert tortoise health assessments as a function of season, location, age (adult vs. juvenile), foraging behavior, evidence of clinical signs of disease, body condition score, and sex. Our results indicate that more ticks were found on tortoises in the summer than in any other season. Ticks were observed more frequently on captive tortoises versus wild tortoises, and more ticks were likely to be present on adult tortoises than on juveniles. Ticks were also more likely to be observed on tortoises that lacked evidence of foraging and on tortoises with observed clinical signs of disease. These findings provide valuable insights into the biology of ticks in relation to tortoises that may be useful for management of both captive and free-living threatened tortoise populations where ticks are detected. Our study also may improve understanding of potential tick-borne disease dynamics in the Mojave desert tortoise habitat, including Borrelia sp. carried by Ornithodoros ticks, which cause tick-borne relapsing fever in people.

Chronic phalaris toxicity (CPT) is a neurological disease caused by animals ingesting toxins produced by early growth stages of Phalaris aquatica, a pasture plant introduced to the southeastern regions of Australia post colonization. Little is known about the clinical progression of CPT in wildlife, as incidents are sporadic and predominantly reported when animals are in the end stages of disease and in a poor welfare state. We studied a cohort of 35 eastern gray kangaroos (Macropus giganteus) affected by CPT to clarify clinical prognosis and survival rates. Kangaroos were captured in May, June, and July of 2022 at Plenty Gorge Parklands, Victoria, Australia. Each animal was radiotracked for 180 d, clinical progression and disease outcomes monitored twice a week. By the conclusion of the study, 24 animals had died (19 by euthanasia due to deterioration, five found dead). Ten animals survived, with two demonstrating a reduction in clinical signs and eight showing full resolution of clinical signs. One animal was disqualified from the study. The overall survival rate was 29.4% (95% confidence interval 17.5-49.5%). The survival duration of animals that died ranged from 5 to 133 d. There was no difference in survival rate based on sex (P=0.2), age class (P=0.49) or the month of capture (P=0.49). These results suggest that CPT is an important health and welfare concern for at-risk macropod populations, with high case-fatality rates and prolonged clinical durations. Further research to manage the disease via methods such as reducing Phalaris aquatica plant coverage and preventative treatments for animals is warranted to reduce disease incidences and improve disease outcomes in wildlife populations.

Toxoplasma gondii, a parasitic protozoan, may infect most warm-blooded animals, including humans and carnivores. Our study focused on alien-invasive American minks (Neogale vison) and domestic cats (Felis catus) in the Valdivian Temperate Rainforest, Chile. The main goal was to investigate the relationship between their dietary habits and T. gondii exposure in the Valdivia River watershed. To detect T. gondii exposure, blood serum samples from 49 domestic cats and 40 American minks were analyzed using an ELISA, and stable isotope analysis of δ15N and δ13C from vibrissae was performed to determine the dietary habits of both species. Relationships between T. gondii exposure and dietary habits were explored using generalized linear mixed-effects models. American minks that were T. gondii seropositive exhibited a broader prey range compared to seropositive domestic cats, with minimal dietary overlap between the two groups. Exposure of domestic cats to T. gondii had no significant association with any isotope value or prey item in their diet. In American minks, we found a positive and significant association between the proportion of Domestic chicken (Gallus gallus domesticus) in the diet and high δ15N values with T. gondii exposure. This suggests that domestic species prey related to anthropogenic areas, and the consumption of high-trophic-level prey, may contribute to T. gondii exposure in American minks. Conversely, contrary to previous hypotheses, consumption of rodents showed no significant association with T. gondii exposure in either species. Our findings emphasize the importance of further research to investigate trophic interactions in the transmission dynamics of T. gondii in the Valdivian Temperate Rainforest.