Journal of Wildlife Diseases最新文献

The history of wildlife pathogens in time and space impacts current understanding, detection, and management of infectious diseases, which may best be appreciated dynamically at a local level. As in the rest of the USA, over the past two centuries the epizootiology, prevention, and control of rabies in Alabama has changed significantly. Canine rabies was reported in Alabama during the USA civil war and predominated until after World War II. Appreciation of wildlife rabies grew only after the control of rabies in dogs. During the 1950s, rabies in gray foxes (Urocyon cinereoargenteus) spread throughout the southeastern USA but declined unexpectedly in the ensuing decades. By the 21st century, besides multiple variants of rabies virus in bats, the only extant mesocarnivore reservoir was the raccoon (Procyon lotor). Currently, Alabama represents the westernmost extent of the raccoon rabies virus variant in the USA. Historically, rabies case detection evolved from passive reporting dependent on clinical signs towards enhanced, laboratory-based surveillance. Control progressed from host population reduction toward prevention by oral rabies vaccination of wildlife in combination with comprehensive vaccination of companion animals and postexposure prophylaxis in humans. Today, modern disease management is exemplified in Alabama via a One Health context, as reflected in this systematic review.

Abstract: Ophidiomyces ophidiicola (Oo) is a fungus primarily affecting the skin of a wide range of snake species. Ophidiomyces ophidiicola has been found in snakes under human care as well as in free-ranging snakes, and the number of documented infections in free-ranging snakes from Europe is increasing. To better understand the distribution of Oo in snakes in Germany, 329 samples were collected from 328 free-ranging snakes from 47 different locations in Germany in 2021-22. Samples included swabs (n=188), shed skins (n=134), and carcasses (n=7) from six different species: 140 dice snakes (Natrix tessellata), 68 European common adders (Vipera berus), 62 Aesculapian snakes (Zamenis longissimus), 29 smooth snakes (Coronella austriaca), 17 whip snakes (Hierophis viridiflavus), and 12 grass snakes (Natrix natrix). Sampled animals were examined for the presence of skin lesions and samples were screened for Oo by real-time PCR (qPCR). Ophidiomyces ophidiicola was detected in 30/328 snakes (9.1%), including dice snakes (23/30, 77%), Aesculapian snakes (5/30, 17%), and grass snakes (2/30, 7%). No differences were found in the likelihood of detection of Oo between individual colubrid species, but colubrid snakes were significantly more likely to be Oo positive than were viperid snakes (Fisher's exact test, P=0.001). Skin lesions were observed in 37/328 snakes (11.3%), of which 8/37 (22%) were Oo positive by qPCR. Significant differences were found in Oo prevalences depending on the presence of skin lesions, and Oo positive snakes were more likely to have skin lesions compared to snakes that were Oo negative (OR=3.37 [95% confidence interval 1.38-8.26%; P<0.05]).

The Peregrine Falcon (Falco peregrinus) is a species of conservation interest throughout much of eastern North America, and management efforts for the species are widespread. Peregrines are at risk for exposure to Trichomonas spp. because of their tendency to take pigeons and doves (Columbiformes) as prey. We investigated the prevalence of Trichomonas spp. in wild nestling Peregrine Falcons banded in nests in Kentucky, USA. We tested throat swabs collected from 266 Peregrine Falcons during 2005-23. A total of 21 birds tested positive for Trichomonas spp.; none of the falcons that tested positive were resighted as adults. We treated a subset of nestlings for Trichomonas spp. infection, including two in the nest (without removal), two nestlings temporarily removed from the nest for treatment, and 10 placed with wildlife rehabilitators for treatment. Rehabilitated nestlings were released at an age of ≥75 d. However, we did not confirm any benefits to survival from treatment. Trichomonosis may hinder Peregrine Falcon nestling survival in certain areas, especially urban locations.

Isolation of protostrongylid larvae from white-tailed deer (Odocoileus virginianus) from northern Minnesota (n=60), Wisconsin (n=19), and Michigan (n=38), USA, and confirmation of species identities via DNA sequencing, revealed Parelaphostrongylus tenuis, Parelaphostrongylus andersoni, Varestrongylus cf. alpenae and five unidentified genetic lineages. This has implications for moose (Alces alces) conservation.

The swift fox (Vulpes velox) is a small canid species occupying mixed and short-grass prairie ecosystems across western North America. Populations have declined across a large portion of their historical habitat distribution, mainly due to anthropogenic influences. Although some populations appear to be rebounding, the swift fox is classified as a species of greatest conservation need in Wyoming, USA, due to threats from predation, vehicular collisions, and habitat alterations that increase potential contact with humans and domestic animals. This potential contact with other species puts swift foxes at risk from infectious disease transmission, potentially resulting in morbidity or mortality. There are few published studies about disease seroprevalence and presence of parasites from swift foxes within Wyoming. Serum samples (n=103) and fecal samples (n=113) from live swift foxes were opportunistically collected from southeastern Wyoming (2009 and 2020-24) and submitted for testing. Serum samples were assessed for antibodies using an indirect fluorescent antibody test, canine parvovirus (CPV), and virus neutralization tests, canine distemper virus (CDV) and canine adenovirus (CAV). Fecal samples were tested using a standard fecal float and a real-time PCR for Echinococcus spp. and Echinococcus multilocularis. Not all samples could be tested for every assay. Overall, 58 (73%; n=80) foxes were seropositive for CPV, 5 (19%; n=27) for CAV, and 1 (2%; n=53) for CDV. Toxascaris leonina was the most commonly detected (31%; n=44) gastrointestinal parasite, and Echinococcus spp. was detected in one individual (0.9%; n=113). These results reveal previously unidentified levels of seroprevalence and lack of difference between age and sex in this species. Continued exploration and surveillance is needed to assist in determining associated morbidity and mortality and to identify risk factors (e.g., domestic canid, other wild canid comingling) contributing to disease transmission within this population.

Liver changes in a Bald Eagle (Haliaeetus leucocephalus) were associated with the presence of Myxidium anatidum. The myxozoan parasites were present in bile ducts. The genus and species were determined using an 18S rRNA PCR combined with sequencing of the product and a BLASTN search.

Wild Turkeys (Meleagris gallopavo) are an important game species in the USA and have experienced population declines in many areas of their range for >10 yr. Among other hypotheses, increased disease prevalence or novel disease emergence could be contributing factors in Wild Turkey population declines. To address some knowledge gaps and further understand the impacts of two important diseases on Wild Turkey populations, we sought to document the prevalence of histomonosis and lymphoproliferative disease virus (LPDV) in Alabama, USA, and to evaluate the spatial epidemiology of LPDV. We collected hunter-harvested Wild Turkey carcasses and paired observational surveys across Alabama during the 2022 and 2023 spring hunting seasons. During necropsies we collected the ceca, which was frozen and stored at -20 °C, and the spleen, which was stored in 70% ethanol at 20 °C or frozen and stored at -20 °C. We screened cecal walls for Histomonas meleagridis DNA and spleens for LPDV proviral DNA by using quantitative PCR and PCR, respectively. We detected H. meleagridis, the disease-causing protozoan for histomonosis, in 0.7% (3/435) of our samples. We detected LPDV proviral DNA in 88.7% (416/469) of our sample of frozen spleens. Our results suggest that evaluation of the impact of histomonosis on Wild Turkey populations is difficult through active surveillance alone. We detected proviral LPDV DNA in Wild Turkeys from nearly every county sampled in Alabama (53/56 counties); however, a generalized linear mixed model did not reveal a statistically significant relationship between LPDV and land cover type. Our findings demonstrate that LPDV is widely distributed with high rates of prevalence in Alabama. Because the effects of these two diseases and others on Wild Turkey population vital rates have not been well established, further work is warranted.

White-nose syndrome (WNS) continues to compromise hibernating Perimyotis subflavus (tricolored bat) populations as it spreads across their geographic range in North America. Despite the presence of the causative agent, the fungus Pseudogymnoascus destructans (Pd), in hibernacula, some tricolored bat populations located near the southern extent of their hibernating range remain unaffected by WNS. We propose that disease progression is absent as these hibernacula, mainly highway culverts, are unsuitable for fungal growth because microclimates fall outside the growth limits of the fungus. Thus, this study investigated the role of hibernaculum microclimate in influencing potential Pd growth and subsequently a hibernaculum's capacity to be an environmental reservoir. We collected microclimate data from multiple types of hibernacula (caves, tunnels, and culverts) near the southern extent where Pd and tricolored bat ranges overlap. Analysis revealed differences in microclimates among hibernaculum types, with culverts exhibiting lower humidity over winter, resulting in reduced fungal growth compared with other hibernaculum types. Caves, which maintained optimal humidity for Pd, had the highest predicted cumulative fungal growth (3.53 cm2), more than double the estimated WNS morbidity threshold (1.54 cm2). The tunnel showed a similar pattern, with a maximum growth of 3.16 cm2. In contrast, culverts, with less suitable microclimates, had the lowest predicted fungal growth (1.78 cm2), only 15% above the morbidity threshold. Although previous research primarily focused on temperature, our findings suggest that relative humidity may be a critical factor, particularly near the southern extent of the geographic range of hibernating tricolored bats. These findings emphasize the importance of considering humidity alongside temperature when evaluating hibernaculum susceptibility to fungal invasion and WNS development. Understanding the impact of microclimate on disease dynamics and bat behavior is crucial for developing effective conservation strategies, particularly for tricolored bat populations near the southern extent of susceptible hibernating populations.

Wild animals are increasingly exposed to a complex array of environmental stressors, including habitat fragmentation, pollution, and emerging infectious diseases, which can interact in unpredictable ways to influence animal health and survival. The European hedgehog (Erinaceus europaeus), recently classified as near threatened on the IUCN red list, faces many of these challenges. This study investigates the relationships between hepatic concentrations of metallic trace elements (MTEs) and health status in free-ranging Belgian hedgehogs, both juveniles and adults, with a focus on hedgehog diphtheric disease (HDD) and a novel circovirus. We analyzed liver samples for essential (zinc [Zn], copper [Cu]) and nonessential (lead [Pb], cadmium [Cd]) MTEs, comparing levels between healthy and affected individuals. Results showed generally moderate MTE levels (Cd: 2.88±4.27 mg/kg dry weight [dw]; Pb: 1.06±1.34 mg/kg dw; Cu: 31.53±39.01 mg/kg dw; Zn: 365.56±282.10 mg/kg dw) compared with other European populations, with the exception of markedly elevated hepatic Zn concentrations, particularly in adults (576.32±200.20 mg/kg dw). Notably, Zn levels were significantly higher in individuals affected by HDD, across both juvenile (P<0.001) and adult (P<0.01) age classes. Although high environmental Zn exposure may predispose hedgehogs to disease, elevated hepatic Zn could also reflect infection-driven redistribution due to inflammation and host immune responses. These findings align with broader evidence linking altered MTE profiles to disease processes in wildlife and suggest a complex, potentially bidirectional interaction between trace element homeostasis and infectious disease. This study highlights the importance of incorporating MTE dynamics into wildlife health surveillance, and suggests that Zn may serve as a potential indicator and mediator of disease in hedgehogs and other free-ranging species.

Wild Turkeys (Meleagris gallopavo, hereafter turkeys), an important North American game species, have experienced declines throughout their eastern range. Growing concern over turkey population sustainability has renewed interest in investigating potential disease threats. We conducted pathogen surveillance in turkeys in three North Carolina, USA ecoregions-Mountains, Piedmont, and Coastal Plain-in 2020-22 to provide baseline data relevant to the southeastern USA. We collected samples from 586 live free-ranging turkeys plus 22 recaptured individuals (n=608: 194 males, 414 females; 159 juveniles, 449 adults) to test for exposure to or infection with selected pathogens. Molecular testing revealed infections with Haemoproteus spp. (57%), lymphoproliferative disease virus (LPDV; 46.8%), Mycoplasma spp. (39.8%), Leucocytozoon spp. (8.8%), and reticuloendotheliosis virus (REV; 3.4%). We detected antibodies to Toxoplasma gondii (21.3%), West Nile virus (WNV; 15.4%), and avian influenza virus (2.0%). No turkey coronavirus, Plasmodium, Borrelia, or Salmonella infections were detected. There were no prevalence differences between sexes, except for REV (females=5%, males=1%). Prevalence was higher in adults than in juveniles for LPDV (adult=52%, juvenile=33%), WNV (adult=19%, juvenile=6%), Haemoproteus (adult=60%, juvenile=49%), T. gondii (adult=24%, juvenile=14%), and Leucocytozoon (adult=11%, juvenile=3%). Prevalence of LPDV differed significantly across ecoregions, with the highest prevalence in the Piedmont (62%), followed by the Mountains (51%) and the Coastal Plain (27%). Prevalence of WNV antibodies was higher in the Piedmont (24%) than in the Mountains (8%). Haemoproteus and Leucocytozoon prevalence increased over a regional gradient, with detections of 24% and 0% in the Mountains, 65% and 6% in the Piedmont, and 85 and 21% in Coastal Plain, respectively. Mycoplasma spp. prevalence was higher in the Mountains (45%) and the Coastal Plain (47%) than in the Piedmont (27%). Our data highlighted sex-, age-, and region-based differences in prevalence for several pathogens, thereby enabling managers to tailor management strategies and researchers to investigate effects of these pathogens on turkey survival and movement.