Babesia is a diverse genus of piroplasms that parasitize the red blood cells of a wide variety of mammals and avian species, including humans. There is a lack of knowledge on the Babesia species of carnivores and mesomammals in the eastern United States and the potential impacts of these species on the health of humans and domestic animals. We surveyed 786 wild mammals in the eastern United States by testing blood, spleen, and heart samples with PCR targeting the 18S rRNA region of apicomplexan parasites. We also performed PCR targeting the cytochrome c oxidase subunit 1 (cox1) region of each unique clade identified with 18S rRNA sequencing. We found a high positivity of Babesia spp. infection in raccoons (Procyon lotor), foxes (Vulpes vulpes and Urocyon cinereoargenteus), and striped skunks (Mephitis mephitis), and low positivity in Virginia opossums (Didelphis virginiana). No Babesia infections were detected in coyotes (Canis latrans), black bears (Ursus americanus), groundhogs (Marmota monax), muskrats (Ondatra zibethicus), or mink (Neovison vison). Skunks carried a diverse number of strains including a potential novel species of Babesia related to B. gibsoni, a strain closely related to a B. microti-like species known to cause disease in river otters, as well as a separate B. microti-like strain. Raccoons primarily carried B. microti-like strains, though there was a high diversity of sequences including Babesia lotori, Babesia sensu stricto MA230, and Babesia sp. ‘Coco.’ Foxes exclusively carried B. vulpes. In addition to Babesia spp., a high positivity of Hepatozoon spp. infection was found in mink, while low positivity was found in raccoons and muskrats. Wildlife in the eastern United States carry a diverse range of Babesia species including several novel strains of unknown clinical significance.

Sarcoptic mange, caused by Sarcoptes scabiei, is a pan-emerging zoonotic disease, affecting new species and expanding into novel geographic locations in recent decades yet the distinct differences in disease syndromes between species remain poorly characterized and understood. This study investigated mange severity, mite burden, and immune response as characterized by dermapathology in sympatric carnivoran species in Pennsylvania, USA, assessing black bears (Ursus americanus), coyotes (Canis latrans), grey foxes (Urocyon cinereoargenteus), and red foxes (Vulpes vulpes). Scabietic and healthy individuals were evaluated using standardized metrics to assess health parameters between infested and healthy individuals and differences in mange disease syndromes between species. Mange severity varied significantly by species. Red foxes and black bears displayed more severe outward signs of mange infestation and higher mite burdens compared to coyotes, which exhibited milder physical and histologic signs of disease. Histologic analyses revealed significant differences in dermatologic lesions; black bears and red foxes more frequently had severe hyperkeratosis, acanthosis, and secondary bacterial and yeast colonization, while coyotes had fewer and milder lesions. In terms of mite detection, tissue digestions were the most sensitive method, followed by cytology and histology. Serological screening detected the highest S. scabiei exposure rates in coyotes (53 %), followed by black bears (37 %), red foxes (17 %), and grey foxes (12 %). Notably, many seropositive coyotes showed no physical signs of mange, suggesting potential resistance or recovery. In contrast, red foxes exhibited severe disease and low seroprevalence, consistent with high mortality and limited recovery. These findings highlight species-specific differences in sarcoptic mange manifestation and host responses. Coyotes may act as reservoirs, contributing to disease persistence in the ecosystem, while red foxes and black bears suffer higher morbidity. This study emphasizes the need for integrated diagnostic and surveillance approaches to improve understanding of S. scabiei epidemiology and inform wildlife management strategies.

The avian influenza virus is a global pathogen with significant health and economic implications. While primarily a pathogen of wild and domestic birds, recent outbreaks of the H5N1 highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4b have caused mortality in a wide variety of mammals, including members of the Canidae family, on multiple continents. Despite sporadic mortality events globally, the epidemiology and pathobiology of H5N1 HPAIV in wild canids remains poorly defined. During 2022–2024, 41 wild canid carcasses (diagnostic cases), including 23 red foxes and 18 gray foxes, were tested for the influenza A virus (IAV) via PCR, with five red fox kits testing positive (12%). Infected animals had variably severe encephalitis, pneumonia, and occasionally myocarditis associated with strong immunolabeling for IAV. Serum from 269 wild canids in Pennsylvania was tested for antibodies to IAV, including 133 samples collected prior to 2021 (pre-H5N1 HPAIV 2.3.4.4b introduction) and 136 collected after 2022 (post-H5N1 HPAIV 2.3.4.4b introduction). All samples collected prior to 2021 were seronegative for IAV. Two coyotes from 2024 were seropositive for IAV but were negative for antibodies to the H5 and N1 subtypes. Collectively, these data suggest that while sporadic H5N1 HPAIV infection and mortality can occur in wild canids, particularly juvenile red foxes, infection was limited in these outwardly healthy and opportunistically sampled animals. Future studies should utilize a risk-based approach to target sampling of wild canids at increased risk for H5N1 HPAIV infection, such as those around waterfowl habitats or spatially around wild bird or domestic animal outbreaks.