Hepatozoon spp. infection in wild canids in the eastern United States.

BACKGROUND: Hepatozoon spp. are apicomplexan parasites known to cause musculoskeletal disease in a variety of animals. Two species are known to infect wild and domestic canids in the US: Hepatozoon canis and H. americanum. METHODS: In this study, blood, heart, and/or spleen samples were collected from 278 wild canids (180 coyotes, 93 red foxes, and 5 gray foxes) in the eastern US and tested via PCR for Hepatozoon. Histology slides of heart and skeletal muscle were assessed for Hepatozoon cysts and associated inflammation when fresh tissue was available (n = 96). RESULTS: Hepatozoon spp. were found in 24.2% (59/278) of individuals, with Hepatozoon canis in 14.0% (34/278) and H. americanum in 10.7% (26/278). One coyote was positive for both H. canis and H. americanum. Foxes were more likely to be positive for H. canis than coyotes (23% and 7% respectively, P = 0.0008), while only coyotes were positive for H. americanum. Of the eight sampled states, H. canis was present in six (Louisiana, North Carolina, Pennsylvania, South Carolina, Tennessee, and Virginia) while H. americanum was found in two southern states (South Carolina and Louisiana). Infection status was positively correlated with myositis and myocarditis, and heart or muscle cysts were found in 83% (5/6) of H. americanum-positive coyotes. CONCLUSION: This survey showed a moderate prevalence of H. canis and H. americanum in states where the parasite was previously unrecorded including South Carolina and Pennsylvania.

Echinococcus Species Infections among Wild Canids in Pennsylvania, USA.

Echinococcus species are zoonotic tapeworms that can impact the health of wildlife, domestic animals, livestock, and humans. Two species of interest in North America are Echinococcus multilocularis and Echinococcus canadensis (Echinococcus granulosus sensu lato). The primary wildlife definitive hosts for E. multilocularis and E. canadensis are similar, including red foxes (Vulpes vulpes), gray foxes (Urocyon cinereoargenteus), coyotes (Canis latrans), and wolves (Canis lupus). These two Echinococcus spp. use different intermediate hosts, including small mammals for E. multilocularis and artiodactylids for E. canadensis. Although historically absent from much of the eastern US, recent reports in new US states (e.g., Virginia, Vermont, Maine, Missouri) highlight the need for Echinococcus spp. surveillance in this region. During 2019-2020, 308 gastrointestinal tracts were collected from wild canids in Pennsylvania and microscopically screened for adult Echinococcus species. Two coyotes (2/155) were co-infected with both E. multilocularis and E. canadensis as determined by molecular confirmation. No red foxes (n=137) or gray foxes (n=16) were positive. These data indicate both Echinococcus species are present in Pennsylvanian coyotes, highlighting the need to better understand the ecological and epidemiological consequences for human and animal health.

A Serosurvey of Multiple Pathogens in American Black Bears (Ursus americanus) in Pennsylvania, USA Indicates a Lack of Association with Sarcoptic Mange.

Infectious diseases, particularly of wildlife, are intrinsically linked to human and domestic animal health. Reports of sarcoptic mange in black bears (Ursus americanus) are increasing in multiple states in the USA and while the reason is unknown, mange in other species has been associated with immunosuppression from multiple causes. Serum from bears across Pennsylvania were collected to determine the seroprevalence of five pathogens important for animal and/or human health: Canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus-1 (CAV), Toxoplasma gondii, and Trichinella sp. from bears with sarcoptic mange as well as bears that were clinically normal. Several of these pathogens, particularly canine distemper virus, are associated with immunosuppression and secondary infections in other hosts. In addition to describing the seroprevalence and relating these findings to data from other regions, statistics were performed to determine if antibodies to any of these pathogens were associated with mange in bears. The overall seroprevalence to these pathogens was as follows: CDV 7.1% (17/240), CPV 16% (15/94), CAV 6.9% (6/87), Toxoplasma gondii 64.9% (194/299), and Trichinella spiralis 3.2% (7/220). While there was no association between mange and antibodies to these pathogens, infection with one or more of these pathogens has implications for bears, other wildlife, domestic animal, and human health.

EXPOSURE OF ALASKA BROWN BEARS (URSUS ARCTOS) TO BACTERIAL, VIRAL, AND PARASITIC AGENTS VARIES SPATIOTEMPORALLY AND MAY BE INFLUENCED BY AGE.

We collected blood and serum from 155 brown bears (Ursus arctos) inhabiting five locations in Alaska, US during 2013-16 and tested samples for evidence of prior exposure to a suite of bacterial, viral, and parasitic agents. Antibody seroprevalence among Alaska brown bears was estimated to be 15% for Brucella spp., 10% for Francisella tularensis, 7% for Leptospira spp., 18% for canine adenovirus type 1 (CAV-1), 5% for canine distemper virus (CDV), 5% for canine parvovirus, 5% for influenza A virus (IAV), and 44% for Toxoplasma gondii. No samples were seropositive for antibodies to Trichinella spp. Point estimates of prior exposure to pathogens among brown bears at previously unsampled locations generally fell within the range of estimates for previously or contemporaneously sampled bears in Alaska. Statistical support was found for variation in antibody seroprevalence among bears by location or age cohort for CAV-1, CDV, IAV, and T. gondii. There was limited concordance in comparisons between our results and previous serosurveys regarding spatial and age-related trends in antibody seroprevalence among Alaska brown bears suggestive of temporal variation. However, we found evidence that the seroprevalence of CAV-1 antibodies is consistently high in bears inhabiting southwest Alaska and the cumulative probability of exposure may increase with age. We found evidence for seroconversion or seroreversion to six different infectious agents in one or more bears. Results of this study increase our collective understanding of disease risk to both Alaska brown bear populations and humans that utilize this resource.