Journal of Wildlife Diseases最新文献

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.

Abstract: Hepatozoon spp. are protozoal organisms that infect a wide variety of animal hosts. Three free-ranging American mink (Neovison vison) from Pennsylvania, USA, were diagnosed with hepatozoonosis either as the primary cause of mortality or as a co-morbidity with canine distemper virus infection or trauma. In all cases, protozoa were detected in the lungs and/or heart with varying severity, as characteristic microgranulomas with intrahistiocytic merozoites as well as fewer distinct meronts. Partial 18S rRNA gene sequence from one case was identical to a Hepatozoon sp. previously detected in mink followed by a Hepatozoon sp. detected in ticks and other mustelid species. This paper expands on the limited knowledge of Hepatozoon spp. infecting North American mustelids and correlates that a previously detected Hepatozoon sp. in mink can cause histopathologic lesions and occasional mortality.

The recent highly pathogenic avian influenza (HPAI) outbreak in Peru devastated seabird populations and was associated with mass mortality events in marine mammals. The first mortality events were observed in coastal Peru in 2022, with the death of hundreds of Peruvian Pelicans (Pelecanus thagus). The outbreak response included health assessments and attempts to use rapid virus detection methods in the field on live and dead birds. Our study compared the FluDETECT Avian rapid antigen screening test that is commonly used in poultry with reverse transcription quantitative PCR (RT-qPCR) for the detection of HPAI virus in Peruvian seabirds. In total, 43 birds across five species were evaluated in this study: Humboldt Penguins (Spheniscus humboldti; n=6), Guanay Cormorants (Leucocarbo bougainvilliorum [Phalacrocorax bougainvillii]; n=19), Peruvian Pelicans (n=13), Kelp Gulls (Larus dominicanus; n=2), and Peruvian Boobies (Sula variegata; n=3). We did not find agreement between the results of the rapid antigen test and the RT-qPCR (Cohen kappa=0.14). The diagnostic sensitivity of the rapid test was low (33%), whereas the specificity was 100%. Based on these findings, we do not recommend the FluDETECT Avian rapid antigen test for influenza screening in seabird species, although given the high specificity, a positive result from this rapid test should be interpreted as a true positive.

Lesion severity scores are often used to monitor individual health outcomes following the incursion of certain wildlife diseases. However, collapsing a complex trait such as pathology onto a single axis can mask critical information about host-pathogen interactions. In this study, we apply multivariate techniques (shape and community analyses) to explore potential patterns of coevolution in a well-studied wildlife disease system: House Finches (Haemorhous mexicanus) infected with Mycoplasma gallisepticum, a bacterium that causes conjunctival pathology that is visible and facilitates transmission. We captured hatch-year House Finches from two USA populations that differ in their history of pathogen exposure: a Virginia population that has experienced seasonal epizootics for >25 yr and a Hawaii population that is naïve to the pathogen. We then experimentally infected the birds with one of two isolates that varied in virulence. The Virginia birds showed milder distortions of the eye rim, reflected as shorter distances traveled through disease space, across isolates than did the Hawaii birds. Although birds expressed an overlapping suite of pathologic descriptors, the high-virulence isolate caused Virginia birds to express certain pathologies at different frequencies, leading to depauperate communities, compared with the Hawaii birds in which pathologies were expressed more evenly. Notably, eversion was expressed in nearly half of all Virginia eye-days (number of days an eye was sampled) with pathology in response to the high-virulence isolate despite relatively mild lesion severity scores. This may indicate that pathologies that can enhance host competence without compromising host fitness will be maintained and even selected for during host-pathogen coevolution, especially in wildlife populations trending toward disease tolerance.

Yellow-eyed Penguins (Megadyptes antipodes; hoiho) are a unique, nationally endangered, and declining species endemic to New Zealand. Between 28 April 2023 and 28 February 2024, histopathologic examination found that six Yellow-eyed Penguins died from septicemia. A Pasteurella sp. was cultured from all six cases and confirmed as Pasteurella multocida in three cases by either MALDI-TOF (n=2) or genome sequencing (n=1). One isolate was confirmed as P. multocida type A:L3 by molecular techniques and genome sequencing. Pasteurella multocida is the causative agent of avian cholera; thus, finding P. multocida confirmed avian cholera as the cause of these deaths. A source for the bacterial infections could not be identified in these cases. Although avian cholera has been previously reported in other penguin species, to our knowledge, these are the first reported cases of P. multocida in Yellow-eyed Penguins. Yellow-eyed Penguins do not nest in dense colonies, and direct contact between birds outside of breeding pairs is irregular, making this case series an unusual presentation for avian cholera. The loss of six individuals, including three of breeding age, will have a significant impact on the mainland Yellow-eyed Penguin population, and the potential for further losses to avian cholera cannot be discounted. This case series illustrates the benefits of multiagency collaboration in monitoring for, and investigation of, potentially new and emerging diseases in threatened species.