Journal of Wildlife Diseases最新文献

Amphibians are the most threatened vertebrate group worldwide, with emerging infectious diseases playing an important role in their ongoing declines. Although the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has received considerable attention, viruses of the genus Ranavirus (Rv) remain less explored, particularly in South America. In this study, we report the first detection of Rv in two threatened amphibian species from Brazil. Specifically, we found infected tadpoles of the redbelly toads Melanophryniscus admirabilis (1.4% prevalence) and Melanophryniscus biancae (24% prevalence) in the southern Brazilian Atlantic Forest. Our findings highlight the need for expanded surveillance and pathogen monitoring in threatened anuran populations, particularly those with limited geographic distributions and threatened with extinction. Understanding Rv dynamics and potential interactions with Bd and other stressors is essential to guiding future conservation strategies for Melanophryniscus spp. and other vulnerable amphibians in the Atlantic Forest biome.

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.

Naturally occurring methylxanthines (MTXs) are plant-derived alkaloids, including caffeine, theobromine, and theophylline. Common sources of these compounds are coffee, chocolate, and tea. Methylxanthine toxicosis has been frequently described in domestic dogs and pet birds, but few reports exist for free-ranging wildlife species. From November 2019 through November 2020, we evaluated 24 American White Ibis (Eudocimus albus) and one Yellow-crowned Night Heron (Nyctanassa violacea) collected from morbidity and mortality events along the Atlantic coast of Florida, USA. Live ibises displayed clinical signs of lethargy, ataxia, and recumbency before their euthanasia. Toxicologic assays performed on liver primarily revealed caffeine and theobromine, with few detections of theophylline. Histologic findings were nonspecific and included diffuse vascular congestion in multiple tissues. We were unable to identify the source of MTX exposure in the clustered ibis mortality events, but several cultivated botanical sources (e.g., native Yaupon holly [Ilex vomitoria]) of MTX grow on Florida's landscape. Additionally, caffeine is a ubiquitous environmental pollutant of both freshwater and marine ecosystems, with anthropogenic inputs from sewage effluent and improper disposal of pharmaceutical products and manufacturers' waste. Our findings underscore the need for broad consideration of the ecotoxicologic impacts of caffeine and related chemicals on free-ranging wildlife species.

Understanding infection dynamics of emerging pathogens, such as Batrachochytrium dendrobatidis (Bd) is crucial for wildlife conservation, especially in highly disturbed urban ecosystems that support diverse host communities. While Bd typically thrives in cool, humid environments, recent studies have shown that it can exhibit plasticity to warmer conditions. Our study was conducted in fragmented urban forests of Guayaquil and Durán, Ecuador, a coastal region characterized by warm temperatures year-round and facing rapid habitat loss. We hypothesized that seasonal changes associated with temperature and precipitation, anuran species richness, host family, and habitat fragment size would influence Bd infection dynamics. We found that Bd prevalence was influenced by season and host taxonomy, with the highest infection rates during the dry season and in the family Leptodactylidae. Specifically, Bd prevalence across all sites was 10.7%; with an overall prevalence of 2.5% during part of the rainy season (February to April), and 26.0% when temperatures and precipitation were lower (May to July). We also found lower amphibian richness in smaller forest fragments and during the dry season, which appeared to amplify pathogen prevalence. Our research elucidates Bd dynamics in seasonally dry tropical coastal forests and highlights the importance of considering variables associated with dry and rainy seasons (i.e., temperature and precipitation) in disease ecology and conservation planning. Understanding these dynamics is essential for safeguarding amphibian populations in the face of ongoing urbanization and climate change.

Nancy Ma's night monkeys (Aotus nancymaae) are significantly impacted by illegal trafficking along the tri-border region between Peru, Colombia, and Brazil. Night monkeys previously used for biomedical research have been released into natural forests along the tri-border region posing a health and conservation threat to local wild monkey populations. We evaluated the health of 55 adult night monkeys during two sampling periods (2018 and 2023) along the tri-border region through clinical evaluation, determination of ectoparasite presence, and through surveillance via PCR of oral swabs and blood samples followed by Sanger sequencing for herpesviruses, orthoflaviviruses, and Mycobacterium tuberculosis complex. Ectoparasites were more commonly found during the dry season (odds ratio=4.18, 95% confidence interval [1.36, 13.99], P=0.015). The presence of herpesvirus and flavivirus was 48.6% (18/37) and 1.8% (1/55), respectively. Sanger sequencing identified two distinct herpesviruses (Aotus nancymaae cytomegalovirus 1 and Aotus nancymaae lymphocryptovirus 1) and one flavivirus (86.18% identity to the Psorophora flavivirus, part of the insect-specific flavivirus lineage II group in South America). Tuberculosis-causing mycobacteria was not detected. Our findings provide molecular evidence that orthoflaviviruses and herpesviruses are detectable in free-ranging night monkeys in the tri-border region, underscoring the importance of future studies to investigate infection dynamics and the prevalence of potential zoonotic pathogens associated with this primate species within the Amazon Basin.

Deciphering the biological and ecological drivers of virus transmission in wildlife requires specific molecular diagnostic tools. Understanding viral shedding routes, loads, and particle infectivity is crucial for assessing transmission dynamics in reservoir hosts and spillover potential to other species, including humans. We investigated coronavirus (CoV) shedding patterns in the endemic Molossid bat species Mormopterus francoismoutoui on Reunion Island. We tested 1,326 fresh feces with two PCR assays: a pan-CoV multiprobe real-time PCR and a quantitative PCR (qPCR) targeting the RdRp gene of the alpha-CoV previously described in M. francoismoutoui. Both assays showed strong agreement, although the qPCR detected 1.55 times more positives. Temporal variation in CoV shedding prevalence was consistent across assays, and no significant differences in RdRp gene copy numbers were observed between adult females and juveniles. Urbanization may increase Molossid bats interactions with humans, livestock, and synanthropic species; a comprehensive assessment of spillover potential of Molossid-associated alpha-CoVs is therefore critical.

Parasites are part of ecosystems and can regulate populations. The diseases they cause may negatively impact wildlife, sometimes linked to the imbalance created by anthropogenic environmental changes. Mexico harbors more than 10% of the world's avifauna, but there have been few studies on gastrointestinal (GIT) parasites in wild birds of Mexico. The aim of this review was to provide a comprehensive summary of knowledge on GIT parasites of Mexican wild birds and offer suggestions for approaches for future parasitological research on birds in Mexico. We analyzed 85 documents reporting gastrointestinal parasites in wild birds in Mexico. Overall, 73 genera and 96 bird species were reported as hosts for gastrointestinal parasites, representing approximately 8.17% of the bird species richness in Mexico, with the Anseriformes and Pelecaniformes being the most studied hosts. A total of 187 gastrointestinal parasite species have been identified to species level; the least studied phyla are Metamonada and Apicomplexa. Gastrointestinal parasites have been detected in 30 states; the central region of Mexico has been best studied. Game and aquatic species have been the most studied hosts, with few parasitological studies on nonaquatic bird species. Further studies are needed to understand the host-parasite relationships in Mexican landbirds, the diversity of parasites, the ecological factors underlying parasitism, and the impact of parasites in Mexican wild birds under anthropogenic changes.

Abstract: Filaroides martis is a respiratory parasite that can infect and cause verminous granulomata in the lungs of susceptible mustelid hosts. The parasite is common in American mink (Neogale vison) throughout their range and has been reported in several other mustelid species in Europe, Asia, North America, Africa, and New Zealand. Here, we describe F. martis infection and associated verminous granulomata in a juvenile female pine marten (Martes martes) admitted to a wildlife hospital in Scotland, UK. The ecology of F. martis in the UK is poorly understood, but it is possible the parasite was cointroduced with American mink imported to Europe during the early 20th century for use in the fur trade. Further investigation is warranted to better our understanding of the ecology and host effects of F. martis in the UK and further afield.

Disease can threaten endangered species by affecting fitness and survival, suppressing population growth and species recovery. Herein, we investigated three gastrointestinal pathogens-Giardia, Cryptosporidium, and Helicobacter-that could negatively affect the endangered Amargosa vole (Microtus californicus scirpensis). We used PCR testing to determine the presence of the target parasites in 76 fecal samples from 71 Amargosa voles collected during summer 2021 in four marshes in Tecopa, California, USA. Overall, 51 (72%) of 71 voles were PCR positive for Giardia microti, 48 (68%) of 71 for Cryptosporidium spp., and 100% for Helicobacter spp. There were no significant associations between G. microti infection and sex, body condition score, or source marsh. Cryptosporidium sp. infection was significantly more prevalent in smaller marshes. More than half of the individuals sampled (39/71, 55%) were PCR positive for both Giardia and Cryptosporidium spp. upon initial sampling. This study provides foundational information regarding environmentally transmitted parasites in populations of Amargosa voles. Further studies are needed to understand and manage the adverse effects of disease and other threats for the survival of the Amargosa vole.

Seal finger is a zoonotic infection that humans acquire from pinnipeds during dissection or handling, or from trauma. This infection is not uncommon among Canadian biologists working with wild pinnipeds. The etiological agent is believed to be mycoplasma bacteria. No comprehensive data on prevalence of oral mycoplasmas in pinnipeds are available. To investigate whether pinnipeds carry oral mycoplasmas, wild (n=148) and captive (n=14) phocids in eastern Canada and pinnipeds (n=38) in a rehabilitation center in California, USA, were sampled from 1996 to 1998. Mycoplasmas were cultured, isolated, and identified using indirect fluorescent antibody tests in a dedicated mycoplasma laboratory, and prevalence by sex, age, age class, and species of seal was determined. A total of 23l mycoplasma isolates were obtained from sampled pinnipeds. In Canadian phocids, Mycoplasma phocicerebrale, Mycoplasma phocae, and Mycoplasma phocirhinis were isolated and identified from wild gray (Halichoerus grypus) and Atlantic harbor (Phoca vitulina concolor) seals, while M. phocicerebrale was isolated from wild hooded (Cystophora cristata) and harp (Pagophilus groenlandicus) seals and from captive gray and harbor seals, including new host and geographic reports. In wild seals, prevalence of M. phocicerebrale was 78% (31/40) in gray, 70% (32/46) in hooded, 44% (11/25) in harbor, and 22% (8/37) in harp seals. In Californian pinnipeds, M. phocicerebrale and M. phocirhinis were isolated and identified from California sea lions (Zalophus californianus), northern elephant (Mirounga angustirostris) seals, and Pacific harbor (Phoca vitulina richardii) seals, also new host and geographic reports. Unidentified Mycoplasma and Ureaplasma spp. were also isolated in wild and captive Canadian and Californian pinnipeds. These new data on the prevalence and identification of oral mycoplasmas in sampled pinnipeds indicate that personnel working with these animals in the field or in captive situations should exercise caution.