Journal of Wildlife Diseases最新文献

Trematodes in the genus Clinostomum develop into large metacercariae that can sometimes achieve high intensity in their second intermediate hosts, potentially causing pathology. Here, we characterize a morbidity event in tiger salamanders (Ambystoma tigrinum) from a freshwater pond in Boulder, Colorado, USA, linked to extreme clinostomid infection. After using necropsy, genomic analysis, and histopathological assessment to record the intensity and pathology associated with infections, we assessed the validity of using noninvasive, image-based methods to quantify infection. Over 2 yr, we recorded in situ video imagery of 62 larval A. tigrinum, of which a subset of larvae was collected for parasitological assessment. In 2022, there was 100% (15/15) infection prevalence of Clinostomum marginatum, with a mean of 3,125 metacercariae per salamander (range: 279-4,075) and a median of 2,949. Dissection and histopathology results indicated that C. marginatum was found in nearly all body tissues and organs of the salamanders. Parasitic infection was closely associated with chronic inflammation and fibrosis around the cysts, with heavily infected hosts exhibiting altered buoyancy and difficulty swimming. The following summer, only 22.0% (6/27) of salamanders were infected with C. marginatum; based on their size, these were probably overwintering larvae from 2022. Infection loads of C. marginatum quantified indirectly via imagery of conspicuous subcutaneous cysts correlated strongly with direct counts via necropsy and were consistent between independent reviewers, highlighting the utility of this non-invasive assessment method. All evaluated A. tigrinum were co-infected with additional parasite taxa. Prevalence of other trematodes included Ribeiroia ondatrae (80%) and Cephalogonimus americanus (77.5%), as well as the nematode Megalobatrachonema elongata (75%). To discern the impact of such high metacercarial burden of C. marginatum on tiger salamander, future work should incorporate experimental approaches to evaluate load-dependent consequences for host growth, survival, behavior, and time to metamorphosis.

Wildlife agencies are tasked with sustaining healthy wildlife populations. Advances in understanding health in wildlife, are, however, suppressed by issues with surveillance. Cost and logistical complexity are leading reasons why ideal surveillance implementation is often infeasible. A particularly important issue in surveillance is the sample size necessary to declare a local wildlife population (or social group) disease free. More precisely, how many animals must we sample to conclude with high confidence that prevalence of an infectious disease is below a specified threshold? Here we show that the answer to this question hinges on the ease of transmission between animals, a factor not considered in standard sample-size formulas. When disease statuses of animals in a local population are positively correlated, such as when a species forms social groups, the sample size requirement needed to declare freedom from disease is substantially lower relative to sample sizes suggested by existing hypergeometric and binomial models. Local wildlife populations or social groups must satisfy key properties for scientists to leverage this saving, but a reduction in cost arising in such a scenario is a welcome win in surveillance implementation.

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first emerged in Wuhan in 2019 and rapidly spread worldwide. During the course of the COVID-19 pandemic, numerous reports highlighted infections of wild animals by SARS-CoV-2. Nevertheless, further research is required to understand the virus potential to infect various animal species, which is crucial for evaluating its future evolution and the potential reemergence of SARS-CoV-2. The total concentration of immunoglobulin G (IgG) represents a valuable yet underused diagnostic parameter for health assessments in wild animals, primarily due to the absence of effective diagnostic tools. A protein A-based indirect ELISA can serve as an efficient method to identify IgG antibodies against different pathogens in wildlife surveillance programs. To develop a multispecies protein A-ELISA for IgG detection against SARS-CoV-2, we used 44 animal species serum samples to ascertain the protein A binding affinity, and 88 serum samples, chosen for the strong binding affinity to protein A, were used to identify IgG antibodies against SARS-CoV-2. The serum samples were obtained from animals housed in Safari Park Dvůr Králové, Czech Republic. The zoo animals are in proximity to humans, facilitating the exploration of potential reverse transmission events of SARS-CoV-2 from humans to animals. Also, they undergo routine veterinary examinations, providing convenient access to blood samples. Therefore, they can be easily used for the development of protein A-based indirect ELISA for wildlife disease surveillance programs. Based on the ELISA results, antibodies to SARS-CoV-2 were detected in the sera of 16 animals. To further confirm these findings, the ELISA-positive samples were subjected to virus neutralization assays. This additional testing revealed the presence of SARS-CoV-2 neutralizing antibodies in the serum of two white rhinoceros (Diceros bicornis) and one Persian leopard (Panthera pardus tulliana).

Highly pathogenic H5N1 influenza A virus (HP H5N1) cases in wild mammals have been increasing globally. Carnivora has been the most affected mammal order; however, the extent of morbidity and mortality in carnivores exposed to HP H5N1 remains undefined. We assessed the presence of antibodies to H5 and N1 in the sera of 16 live-captured bobcats (Lynx rufus) in New York State, USA; reported on postcapture outcomes of HP H5N1-exposed bobcats; and reported on a case of HP H5N1 infection in one bobcat. In 2024, 4/16 (25%) bobcats tested positive for antibodies to H5 and N1. Two were confirmed alive as of November 2024 according to GPS data; the other two were alive as of June 2024, when their GPS collars stopped communicating. Another bobcat, which was negative for HP H5N1 antibodies at capture, died from HP H5N1 infection within 5 wk of capture. Our results provide evidence of bobcats both surviving and succumbing to HP H5N1 infection and highlight the importance of focused health studies paired with monitoring data to better understand exposure, infection, and outcome for novel pathogens and species.

The impacts of white-nose syndrome (WNS) on many bat species in eastern North America have been well documented because of the length of time that the causative agent, Pseudogymnoascus destructans (Pd), has been present and the ability to monitor bat hibernacula in that region. However, the disease outcomes for bat species in western North America are less known because of the more recent arrival of Pd and the challenges associated with monitoring hibernating bat populations in parts of the western US. We report on mortality events involving Yuma myotis (Myotis yumanensis) bats at two locations in King and Benton counties, Washington, US, that were attributed to WNS during the late winters of 2020-21 and 2024, respectively. All bats that were grossly examined had depleted subcutaneous white adipose tissue, tested positive for the presence of Pd, had histopathologic lesions consistent with WNS, and did not exhibit evidence of other disease processes that may have contributed to death. Mortality was likely higher than what was documented because the locations of the Pd-contaminated hibernacula from which the bats originated were inaccessible or unknown and thus could not be surveyed. These findings indicate that Yuma myotis may be highly susceptible to WNS, and close monitoring is warranted to understand how WNS will affect population trends in this (and other) western bat species.

Little is known about the significance of mycoplasmas in different free-ranging bird species. One hypothesis is that the prevalence of mycoplasmas and the influence of vocalization on reproduction are evolutionarily linked. To add another piece of information toward proving or disproving this hypothesis and obtain more information about the clinical relevance of mycoplasmas, choanal swabs from different passerine species presented to a veterinary clinic were examined for mycoplasmas using culture and Mycoplasma genus-specific PCR. When mycoplasmas were detected, the species was identified by sequencing the partial 16S rRNA and 16S-23S rRNA intergenic spacer region. In total, 221 passerines from 34 species and 17 families were sampled. Mycoplasmas were detected in 12% of the Passeriformes and mostly in four families: Sturnidae, Muscicapidae, Turdidae, and Hirundinidae. The most commonly detected Mycoplasma sp. was Mycoplasma sturni; this did not seem to be an obligate pathogen. Additionally, Mycoplasma columborale, Mycoplasma moatsii, and two unidentified Mycoplasma spp. were detected. The results indicate that in some passerine families, mycoplasmas occur with an intermediate prevalence. The rare occurrence of mycoplasmas in many passerine bird species seems to be in accordance with the hypothesis of an evolutionary link between mycoplasma prevalence and the influence of vocalization on reproduction, but the findings of our study could not prove or disprove this hypothesis. Further studies of mycoplasma prevalence in free-ranging passerine populations are needed.

Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy affecting cervids. Transmission occurs through oral and nasal mucosal exposure to infectious prions (PrPCWD), causing cellular prion proteins (PrPC) to misfold. Currently, the approved diagnostic assays for CWD are immunohistochemistry (IHC) and ELISA. While IHC is considered the gold standard, ELISA is used by most diagnostic laboratories as a screening test for free-ranging cervids. Currently, two tissues have been validated for use with the cervid ELISA test: the medial retropharyngeal lymph node (MRPLN) and the obex region of the brainstem. Palatine tonsil has not been validated for use with the ELISA despite trafficking of PrPCWD to the tonsils early in the course of disease in deer. Here we assessed the suitability of palatine tonsil for CWD testing of free-ranging mule deer (Odocoileus hemionus) using two commercially available ELISA kits in conjunction with IHC. We tested paired MRPLN and tonsillar tissues, collected from hunter-harvested and non-hunter-harvested mule deer (n=176) in Wyoming, US, from 2020 to 2024. Our findings indicated 100% agreement between MRPLN and palatine tonsil, with no difference in the performance of the two commercially available ELISA kits, confirming that palatine tonsil can be substituted for MRPLN for CWD surveillance in free-ranging mule deer with high confidence.

Osteochondrosis is a common disease that has been described in several farm and pet species as well as in some wildlife species, including captive roan antelope (Hippotragus equinus), a giraffe (Giraffa camelopardalis reticulata), snow leopard (Panthera uncia), and free-ranging wild boar (Sus scrofa ferus). It has not previously been confirmed in gray wolves (Canis lupus lupus). Postmortem radiographs of three free-ranging, juvenile sibling wolves revealed osteochondrosis in at least one of the glenohumeral joints (GHJs) in all individuals. Whole-body computed tomography and computed tomographic arthrography of both GHJs were performed in one case and suggested bilateral osteochondrosis lesions of the humeral head without cartilage flap formation. Cytologic examination of synovial fluid from the GHJs of this wolf was consistent with degenerative arthropathy. Macroscopic and histopathologic examination of the GHJs confirmed the presence of osteochondrosis manifesta in both males and the female. The identification of this condition highlights the importance of considering osteochondrosis in the differential diagnosis of lameness in both captive and free-ranging wolf populations.

Cattle diseases are considered a major threat to wood bison (Bison bison athabascae) conservation. Johne's disease (JD) is a chronic infectious enteritis caused by Mycobacterium avium subspecies paratuberculosis (Map), that affects domestic and wild ruminants globally and could negatively impact wood bison health. Clinical manifestation of JD in free-ranging or captive wood bison has not been documented. We studied animals in a captive wood bison herd in Alberta, Canada 1) to detect Map in bison clinically suspected of Johne's disease, by histopathology, quantitative PCR (qPCR), and isolation by culture; 2) to identify optimal tissue samples for Map detection; and 3) to identify the strain(s) of Map isolated. Six wood bison were evaluated with clinical signs suggestive of JD. We performed necropsies within 24-48 h after euthanasia and collected 24 tissue samples from each bison. At necropsy, no evidence of thickening or corrugation of the intestinal mucosa was observed in any bison. On histopathologic examination, granulomatous lesions with acid-fast bacilli were more frequent in the paracortex of the midjejunal lymph node (LN) and distal jejunal LN, followed by ileal LN, in comparison to the rest of the tissue samples evaluated. In general, tissue culture had the highest proportion of positive samples, with 62.5% (90/144) of positive samples, followed by F57/IS900 qPCR with 43.1% (56/130), and histopathology with 29.0% (38/131). We concluded that distal jejunum and its associated lymph nodes were the most reliable tissue samples for detecting Map, regardless of tissue autolysis or the absence of visible gross lesions. Finally, using IS1311 PCR-restriction enzyme analysis and single-nucleotide polymorphisms, we identified a type II (cattle) strain, secondary clade, in tissue samples. These findings have practical relevance for field necropsies as they provide evidence to direct selection of preferred sampling sites to detect Map in wood bison and to choose appropriate diagnostic techniques.

The European hedgehog (Erinaceus europaeus) is commonly observed in France, residing near human facilities, and is the most frequently treated mammal species in wildlife rehabilitation centers. Consequently, contacts with humans can lead to the potential transmission of bacteria, such as Staphylococcus aureus, between species. Although the presence of S. aureus, particularly methicillin-resistant S. aureus (MRSA), has been documented in hedgehogs across Europe, the situation in France remains unclear. We assessed 139 hedgehogs representative of those typically admitted to our Wildlife Health Center. Carriage of MRSA was determined, and MRSA-positive individuals were characterized clinically and epidemiologically to identify potential risk factors of MRSA carriage. We found an 18% MRSA carriage rate, with 76% of the strains exhibiting the mecC resistance gene. Adult males constituted 60% of the MRSA-positive cases, predominantly found in spring and displaying skin lesions, particularly "dirty wounds." Multivariate logistic regression identified age, "sex," human density, "dirty wounds" and "respiratory troubles" as significantly associated with MRSA carriage in these hedgehogs. Our study establishes a foundation for improved monitoring of health conditions in French hedgehogs and their MRSA carriage, offering new insights for enhancing biosecurity measures in wildlife rehabilitation centers by pinpointing high-risk individuals.