Journal of Wildlife Diseases最新文献

Ranaviruses (Iridoviridae) and chytrid fungus (Batrachochytrium spp.) cause globally reportable diseases affecting a wide array of amphibians. Both pathogens are well documented in the US and have caused local or regional scale mortality events for susceptible amphibians. Over a period of 8 y (2012-2019), we tested salvaged amphibians collected during amphibian audio survey work across the central, southeastern, and coastal areas of Texas, US. Individuals of 7/8 anuran taxa tested positive for either or both pathogens, as did individuals in counties with large sample sizes (i.e., n>25) across taxa. Ranavirus prevalence was high in 2012 (67%) but decreased to 5% by 2019. Conversely, chytrid fungus prevalence started low in 2013 (4%) but increased to 20% by 2019. The detection of both pathogens in any individual was consistently rare throughout the period. Although salvage of specimens during annual fieldwork adds permitting requirements, handling time, and curation effort, we argue that this additional effort significantly contributes to regional pathogen surveillance. Therefore, it should be considered a standard approach for the extensive array of roadway-based herpetofaunal surveys conducted each year.

Chronic wasting disease (CWD) is a prion-associated transmissible spongiform encephalopathy (TSE) that causes fatal neurodegeneration in cervids. One promising method for CWD surveillance is the use of detection dogs trained to differentiate between fecal matter from CWD-positive (infected) and CWD-negative (noninfected) deer. However, using actual fecal matter during the training process confers a biohazard risk. Chronic wasting disease detection dogs trained on fecal matter can differentiate between CWD-positive and CWD-negative training aids, including cotton aids, which are inexpensive and simple to use. However, as most dogs in an applied setting would instead be trained on aids and tasked with finding actual fecal matter in the field, this study examined 1) the extent to which dogs initially trained on CWD-incubated cotton can discriminate between fecal samples from CWD-positive and CWD-negative deer; and 2) the impact of substrate form (cotton ball or cotton roll) on the dogs' detection accuracy. Results show that dogs (n=5) maintained an accuracy of >80% during training while discriminating between cotton ball training aids that had been incubated (noncontact) with deer fecal samples confirmed as either CWD-positive or CWD-negative. When tested with cotton ball training aids incubated with novel samples, dogs (n=4) showed 73% sensitivity and 77% specificity. When presented with deer fecal samples, dogs showed a sensitivity of 50% and a specificity of 90%. The type of cotton (ball or roll) did not significantly influence performance. In sum, cotton aids can be used to train dogs to detect the CWD odor profile effectively. However, an initial reduction in sensitivity suggests that integrating exposure to target fecal matter may enhance detection performance.

The recent expansion of the European wildcat (Felis silvestris silvestris) and increasing numbers of domestic cats in Germany are leading to more interactions between domestic cats and wildcats. Not only hybridization, but also the reciprocal transmission of pathogens may occur. This could threaten wildcat populations, or they may act as a reservoir for their domestic relatives. In this study, 102 effusion fluid samples collected from wildcats found dead between 2020 and 2022 in the German federal state of Rhineland-Palatinate were serologically tested for antigens of and specific antibodies against viral pathogens typically found in domestic cats (feline herpesvirus [FHV], feline calicivirus [FCV], feline parvovirus [FPV], feline immunodeficiency virus [FIV], feline coronavirus [FCoV], and feline leukemia virus [FeLV]). Antigens of and/or specific antibodies against at least one virus were detected in 59% of the wildcats. Detected prevalences of specific antibodies against FHV (22.5%), FCV (20.6%), FPV (13.7%), FIV (0%), and FCoV (17.6%) were each 0-22.5%. The prevalence of antigens of FeLV was 28.4%. The high prevalence detected for FeLV antigens possibly shows that wildcats form a reservoir for this virus, as the prevalence in domestic cat populations is significantly lower.

Bacteriome characterization studies can provide insights into the microbial ecology associated with disease. We collected western pond turtles (Actinemys marmorata and Actinemys pallida) from six San Francisco Bay Area, California, USA, ponds; assessed their shells for lesions; and collected shell swabs and keratin scrape samples to evaluate bacteriome differences between the whole shell (swabs) and the affected tissues (scrapes). We quantified shell lesion type and prevalence by using visual inspections of photographs collected of the plastron and carapace and then applied 16S rRNA amplicon sequencing to characterize the associated bacteriomes of shells that observed pits, ulcerations, or no lesions. We observed shell lesions at high frequencies throughout our sites, with larger individuals (>100-mm plastron length) more likely to possess injuries. We saw no differences in alpha diversities between shells presenting with lesions and those on which we did not observe lesions; however, swab samples showed higher bacterial richness than keratin scrapes. The bacterial composition within the scrapes was influenced by pond location and then lesion presence. We observed a higher relative abundance of Actinobacteriota, Bacteroidota, Cyanobacteria, and Deinococcota in the shell keratin microflora of turtles with shell lesions. Because western pond turtles are under consideration for listing under the Endangered Species Act of 1973 in the USA, understanding patterns of shell disease pathologies and the bacteria associated with disease is imperative for the management of current populations.

Abstract: Neospora caninum is an obligate intracellular protozoan parasite that causes hind-limb paralysis in dogs and abortions in cattle. Recurrent storms of abortions in cattle in Australia are estimated to cause an economic loss of AU$100 million each year, but the source of infection in cattle (i.e., via wild or domestic definitive hosts) remains to be established. We aimed to determine potential sources of horizontal transmission of N. caninum after recent evidence that wild dogs (Canis familiaris) shed N. caninum oocysts in Victoria, Australia. To determine infection levels among wild dogs, samples were collected from three sites in Victoria (n=52) in areas of high wild dog population density (Mansfield, Swifts Creek, and Tallangatta), and N. caninum detection was determined by PCR analysis of blood and duodenal samples. Based on the PCR assay of combined duodenal samples (flotation of duodenal content and just duodenal content), this study detected N. caninum in the fecal material of 11% of wild dogs in Mansfield and 21% of wild dogs in Swifts Creek. This study provides further insight into the possible role of wild dogs as a reservoir of N. caninum in Victoria.

Pansteatitis can be fatal and contribute to wild crocodilian population declines. We documented lesions consistent with pansteatitis in two wild American alligators (Alligator mississippiensis) from South Carolina and Mississippi, USA. These findings extend our knowledge of pansteatitis in wild crocodilians, for which few observations exist beyond Nile crocodiles (Crocodylus niloticus).

The susceptibility of white-tailed deer (WTD; Odocoileus virginianus) to SARS-CoV-2 has resulted in WTD being one of the most studied wildlife species during the COVID-19 pandemic. However, WTD specimen collections for SARS-CoV-2 research and surveillance have largely been opportunistic. Our objective was to evaluate the detection of SARS-CoV-2 neutralizing antibodies (NAbs) in WTD serum, plus two additional WTD biological sample types, using a blocking ELISA previously used for WTD serum. The two additional sample types evaluated were eluted Nobuto filter-paper strips (FPSs) from heparinized whole blood collected perimortem from 34 WTD and serosanguinous fluid collected postmortem from the thoracic cavity of 34 WTD. A true NAb prevalence of 88% was established from the serum samples. The FPS eluates performed most poorly (56% apparent prevalence; 57% sensitivity; 50% specificity), followed by serosanguinous fluid (88% apparent prevalence; 87% sensitivity; 0% specificity). Serosanguinous fluid appeared to better reflect the WTD population's true seroprevalence, although sensitivity decreased to <90% for both nonserum biological sample types. As studies are being developed to better understand the ecology of SARS-CoV-2 infections in WTD and other wildlife, it is important to consider the sample type being assessed, because sensitivity may vary greatly.

A free-ranging adult female mule deer (Odocoileus hemionus) from Wyoming, USA, was euthanized due to an open wound on its head. Postmortem examination yielded a diagnosis of multicentric B cell lymphoma associated with severe skin ulceration. Sequencing of frozen neoplastic tissue found no evidence of an exogenous viral etiology.

Pathogens of domestic dogs have been reported in various carnivorans worldwide. Canine distemper virus (CDV) has been responsible for lethal outbreaks and population declines. Data are scarce regarding CDV outbreaks and their impact on South American canids. An eco-epidemiological investigation of a disease outbreak in a free-living population of Pampas foxes (Lycalopex gymnocercus) in a protected area (reserve) in southern Brazil began after locals informed our team of three foxes in the reserve showing signs of incoordination and seizures. Two carcasses of recently dead foxes were recovered and tested for CDV and rabies. Additionally, samples from 22 Pampas foxes live trapped in the study area were analyzed. Samples of the two dead foxes were positive for CDV antigen, and one of them for the presence of CDV RNA. None of the animals were positive for rabies virus. Analysis of a sequence from the CDV hemagglutinin gene allowed the classification of the CDV strain within the South America 1/Europe 1 (SA1/E1) clade, with high identity with other strains previously identified in domestic dogs. Approximately 90% of live-trapped Pampas foxes were seropositive for the presence of anti-CDV antibodies, and two of them showed myoclonus, indicating an outbreak of CDV in a population of free-ranging Pampas foxes in southern Brazil, possibly due to a spillover from domestic dogs.