Journal of Wildlife Diseases最新文献

Using molecular testing and serology, we investigated Reunion Harrier (Circus maillardi) exposure to avian influenza virus, West Nile virus, and infectious bronchitis virus. We detected influenza virus antibodies in 2 of 73 birds and hypothesized that infection might occur by consumption of poultry.

Abstract: Mannheimia granulomatis-associated lesions have been poorly described compared with those associated with other members of the Pasteurellaceae family; they include pneumonia, panniculitis, and keratoconjunctivitis in domestic and wild ruminants and hares. We describe 15 cases of roe deer (Capreolus capreolus) showing M. granulomatis-infected oral lesions that were detected in France between 2016 and 2023. Comprehensive necropsies were performed, with additional analyses based on findings. All deer were >15 mo of age on the basis of tooth eruption. They were thin (1/15), cachectic (13/15), or of unknown body condition (1/15). They exhibited multiple cryptic millimetric to centimetric caseous granulomas within the lips, tongue, or cheeks (13/15); pyogranulomatous lymphadenitis of a mandibular lymph node (1/15); or necrosuppurative mandibular osteomyelitis with bone proliferation (1/15). Histopathologically, oral lesions of 10/15 animals showed multifocal, severe, chronic pyogranulomatous cheilitis, glossitis, or stomatitis with intralesional Gram-negative bacterial colonies lined by Splendore-Hoeppli material. Amyloidosis was detected in 4/11 animals for which tissues were submitted for microscopic examination, affecting the abomasum, the spleen, and a minor salivary gland in, respectively, 4/6, 3/5, and 1/8 animals for which the relevant organs were assessed histologically. Amyloid deposits showed strong immunoreactivity with a murine monoclonal antibody directed against amyloid AA. AA amyloidosis, never previously described in roe deer, was considered secondary to chronic inflammation. Mannheimia granulomatis was cultured and identified biochemically or by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in oral lesions of all individuals. Coinfection with other bacterial species was sporadically identified. We considered the chronic emaciation and death of these animals to be multifactorial, involving oral lesions, secondary amyloidosis when present, parasitic infestation of variable severity, and probably environmental factors. Further investigation is needed to understand the epidemiology and pathogenesis of M. granulomatis infection in roe deer, including a possible propensity to emerge as temporal and geographic clusters and to induce AA amyloidosis.

Birds are frequently stressed by their exposure to parasites and pathogens. The heterophil to lymphocyte (H:L) ratio has been proposed as a measure of physiological stress. This study investigates the prevalence of the bacterial pathogen Mycoplasma gallisepticum and Haemosporidia in Mexican House Finches (Haemorhous mexicanus). To test the extent to which pathogens stress their hosts we compared total and differential leucocyte counts in four groups of birds with different infection statuses: birds co-infected with M. gallisepticum and haemosporidia, birds infected with either M. gallisepticum or haemosporidia, and birds infected with neither. We hypothesized that co-infected birds would exhibit higher physiological stress, reflected in leukocyte parameters, plus, based on previous experiments, that both M. gallisepticum and haemosporidia would benefit from the presence of each other. We found that 73.6% of House Finches were infected with M. gallisepticum, and 43.1% with haemosporida. Both pathogens had a higher load in co-infected birds. Higher H:L ratios were found in co-infected birds compared to birds with a single infection. The study highlights the complexity of immune responses under co-infection. Our results contribute to the understanding of host-pathogen interactions and stress physiology in wild birds, highlighting the importance of hematological parameters as indicators of stress and providing insights into the ecological impacts of pathogen infections in avian populations. This emphasizes the significance of studying leukocyte profiles in the wild.

Sporadic cases of dermatosis have been reported in wild Ōkārito Rowi (Apteryx rowi), a species of brown kiwi, for over a decade. The disease exhibits distinctive features, including lesions, lichenification, and feather loss. Swab samples and full-thickness skin biopsies were collected during a survey of affected kiwi in 2023 for a metatranscriptome-based, total infectome investigation to identify any possible microbial agents associated with the disease. Our approach identified novel viruses as well as a species of nematode in high relative abundance. We found a highly abundant hepacivirus within the Flaviviridae, but only in some mild cases of dermatitis across all sample types, and in both active and chronic infections. In addition, we found a significant shift in the taxonomic composition of the nonviral microbiome within severe chronic dermatitis cases, particularly an increased abundance of transcripts from a Eucoleus sp. parasitic. Although determining the primary cause of disease in critically endangered wildlife such as Rowi remains challenging, our detection of novel and highly abundant microorganisms opens new lines of inquiry to investigate their potential association with dermatosis in this nationally iconic species.

Bog turtles (Glyptemys muhlenbergii) are critically endangered semiaquatic turtles inhabiting fens and bogs along the east coast of the US. Threats to their survival include habitat loss from development, roads, altered hydrology, ecological succession, proliferation of invasive plants, poaching, and infectious disease. In response to an increase in bog turtle mortality and concerns about their health, we assessed bog turtle health and pathogen prevalence across five states-New York, Pennsylvania, New Jersey, Delaware, and Maryland-between 2014 and 2022. Adenoviruses, specifically barthadenovirus, or atadenoviruses, siadenoviruses, and testadenoviruses, have been associated with infection and disease in chelonians. To determine whether adenoviruses were present in free-ranging bog turtle populations, we tested archived choanal-cloacal swabs by PCR. Overall, 26 (49%) of 53 pooled samples collected between 2014 and 2018 and 9 (30%) of 30 samples collected in 2022 were positive for adenovirus. The DNA sequence and phylogenetic analyses revealed at least four distinct and novel lineages: Glyptemys adenovirus 1 (a testadenovirus first detected in Delaware and New Jersey in 2014 and in New York and Pennsylvania in 2016), Glyptemys adenovirus 2 (a testadenovirus detected in New Jersey and Pennsylvania in 2014), Glyptemys adenovirus 3 (an unclassified adenovirus detected in New Jersey in 2016), and Glyptemys adenovirus 4 (a siadenovirus detected in Maryland in 2016). None of these adenoviruses were associated with clinical signs or disease; however, knowledge of which pathogenic organisms are circulating in the bog turtle populations can inform decisions on monitoring, species recovery efforts, and captive breeding programs.

In the Canadian North, trichinellosis is a zoonotic disease that is primarily transmitted by the consumption of improperly cooked walrus (Odobenus rosmarus) and bear (Ursus spp.) meat. Trichinella spp. infections in other wildlife provide information about where transmission occurs, the species present, and the potential risk of transmission to humans. Wolverines (Gulo gulo) can serve as a sentinel species, due to their scavenging behavior, high trophic level, and high larval burden when infected. We determined the prevalence, intensity, and genetic diversity of Trichinella infections in wolverines in Churchill, Manitoba, Canada, and compared these results with those of studies conducted in other northern Canadian provinces. Larvae were found in 41% (9/22) of hosts, with a mean intensity of 5.93 larvae per gram of tongue tissue. The DNA sequencing of the cytochrome b gene confirmed that all hosts were infected with Trichinella nativa and that diversity was limited with only two distinct haplotypes recovered. The presence of T. nativa in wolverines indicates that this parasite is being maintained in a sylvatic cycle and that humans could be at risk of transmission in northern Manitoba.

Fungal pathogens of reptiles are commonly diagnosed, with Aphanoascella galapagosensis known to affect Galapagos giant tortoises (Chelonoidis spp.), although the implications of this fungus for the health and well-being of these unique species remain understudied. Therefore, the goal of this study was to explore health and environmental variables that may be associated with white shell lesion coverage associated with A. galapagosensis in free-living Galapagos tortoises. For 200 western Santa Cruz tortoises (Chelonoidis porteri) and 70 Alcedo tortoises (Chelonoidis vandenburghi), the percentage of fungal lesion coverage was calculated based on images taken from six different projections per individual, including the carapace and plastron. White lesion shell coverage was compared between species and correlated with hematology and blood chemistry parameters, season, elevation, shell integrity (i.e., scratches, lesions, and fractures), and land-use type. A higher percentage of carapacial fungal white lesion coverage was found in western Santa Cruz tortoises (3.3%) than Alcedo tortoises (0.055%). In both species, a positive correlation was found between fungal white lesion coverage and lymphocyte counts. In addition, tortoises sampled in more humid areas had a higher prevalence of fungal coverage. This study indicates that fungal coverage may be influenced by environmental factors and may affect the overall health status of critically endangered Galapagos giant tortoises.

Galapagos giant tortoises are the largest terrestrial vertebrates and one of the most iconic species of the Galapagos islands. Their populations continue to be endangered because of multiple factors, mostly driven by anthropogenic activities. In recent years, the presence of novel infectious agents of potential conservation concern, including two adenoviruses and two herpesviruses, has been reported in some Galapagos tortoise species. With the aim of describing the presence and prevalence of these pathogens in additional tortoise species, we collected oral, ocular, and cloacal swabs from 99 free-living tortoises from San Cristobal (Chelonoidis chathamensis) and Isabela islands (Chelonoidis vicina and Chelonoidis guntheri) and screened these for the presence of herpesvirus and adenovirus by PCR. We detected Chelonoidis adenovirus 1 (CheAdV1) and Chelonoidis adenovirus 2 (CheAdV2) in all sampling locations, whereas we did not detect herpesvirus in any tortoises. Phylogenetic analyses revealed that San Cristobal nucleotide and amino acid sequences clustered in a clade with CheAdV1, whereas the Isabela nucleotide and amino acid sequences clustered together with CheAdV2. This contributes additional information regarding tortoise viral distribution in the Galapagos Archipelago. We recommend long-term health surveillance of tortoises and other wildlife species to inform conservation actions in the Galapagos involving captive-breeding and rewilding programs.

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.