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At least 397 records · Page 22Linked to original sources

USGS2023

Survey for selected parasites in Alaska brown bears (Ursus arctos)

To assess infection with or exposure to endo- and ectoparasites in Alaska brown bears ( Ursus arctos ), blood and fecal samples were collected during 2013–17 from five locations: Gates of the Arctic National Park and Preserve; Katmai National Park; Lake Clark National Park and Preserve; Yakutat Forelands; and Kodiak Island. Standard fecal centrifugal flotation was used to screen for gastrointestinal parasites, molecular techniques were used to test blood for the presence of Bartonella and Babesia spp., and an ELISA was used to detect antibodies to Sarcoptes scabiei , a species of mite recently associated with mange in American black bears ( Ursus americanus ). From fecal flotations ( n =160), we identified the following helminth eggs: Uncinaria sp. ( n =16, 10.0%), Baylisascaris sp. ( n =5, 3.1%), Dibothriocephalus sp. ( n =2, 1.2%), and taeniid-type eggs ( n =1, 0.6%). Molecular screening for intraerythrocytic parasites ( Babesia spp.) and intracellular bacteria ( Bartonella spp.) was negative for all bears tested. We detected antibodies to S. scabiei in six of 59 (10.2%) individuals. The relatively low level of parasite detection in this study meets expectations for brown bear populations living in large, relatively undisturbed habitats near the northern edge of the range. These results provide a contemporary understanding of parasites in Alaska brown bears and establish baseline levels of parasite presence to monitor for changes over time and relative to ecologic alterations.

Alaska↗

USGS2023

Evaluating baits with lufenuron and nitenpyram for flea control on prairie dogs (Cynomys spp.) to mitigate plague

Plague, caused by Yersinia pestis , is a widespread threat to endangered black-footed ferrets ( Mustela nigripes ) and their primary prey, prairie dogs ( Cynomys spp.). Wildlife biologists most commonly manage plague using insecticides to control fleas, the primary vectors of Y. pestis . We tested edible baits containing the insecticides lufenuron and/or nitenpyram in prairie dogs. During a laboratory study, we treated 26 white-tailed prairie dogs ( Cynomys leucurus ) with lufenuron at 300 mg/kg body mass. All animals remained clinically healthy over the 9 wk monitoring period. Although serum lufenuron concentrations were >130 ppb in two treatment groups at week 1, concentrations declined to ≤60 ppb after 3 wk in non-torpid prairie dogs and after 7 wk in torpid prairie dogs. In a field experiment, we tested baits containing a combination of 75 mg lufenuron and 6 mg nitenpyram, respectively, in black-tailed prairie dogs ( Cynomys ludovicianus ). We uniformly distributed baits at 125 baits/ha on two plots (treated once) and 250 baits/ha on two plots (each treated twice 4.4 wk apart). Following treatments, flea abundance increased on prairie dogs and remained stable in burrows. Our findings indicate that baits containing lufenuron and nitenpyram, at the reported treatment rates, are ineffective tools for flea control on prairie dogs. Future experiments might evaluate efficacy of higher doses of lufenuron and nitenpyram, and repetitive treatments at differing intervals over time to evaluate potentially therapeutic treatments.

Journal of Wildlife Diseases↗

USGS2023

A mixture of Nalbuphine, Azaperone, and Medetomidine for Immobilizing Ringtail (Bassariscus astutus)

We evaluated a combination of nalbuphine HCl (40 mg/mL), azaperone tartrate (10 mg/mL), and medetomidine HCl (10 mg/mL), a combination known as NAM or NalMed-A, in 23 ringtails ( Bassariscus astutus ) during 29 handling events for a radio-collaring study in southern Oregon, US, from August 2020 to March 2022. The combination was delivered to ringtails by hand injection at 0.075 mL NAM per estimated 1 kg body mass. The mean (± standard deviation, SD) dosage calculated post hoc was 3.366 (±0.724) mg/kg nalbuphine, 0.841 (±0.181) mg/kg medetomidine, and 0.841 (±0.181) mg/kg azaperone. All captured ringtails were effectively immobilized with a mean (SD) induction time of 13.24 (±3.57) min. The medetomidine and nalbuphine components were antagonized with a combination of atipamezole and naltrexone HCl with a mean (SD) recovery time of 2.48 (±1.94) min. This combination appeared to be safe and effective for immobilizing ringtails with a low volume dose, smooth antagonism, and rapid recovery. In addition, NAM does not contain any drugs that are US Drug Enforcement scheduled, which makes it useful for immobilization procedures by wildlife professionals in the US.

Journal of Wildlife Diseases↗

USGS2024

Comparison of butorphanol-azaperone-medetomidine and nalbuphine-medetomidine-azaperone in free-ranging elk (Cervus canadensis) in Pennsylvania, USA

Chemical immobilization is commonly used to capture and handle free-ranging elk ( Cervus canadensis ). Butorphanol-azaperone-medetomidine (BAM) and nalbuphine-medetomidine-azaperone (NalMed-A) are compounded drug combinations that are lower-scheduled in the US than drugs historically used for elk immobilizations. We compared BAM and NalMed-A for immobilization of free-ranging elk using free-darting and Clover trapping. From January 2020 to April 2022, 196 female elk were immobilized in Pennsylvania, USA. We report vital rates, induction and recovery times, and the need for supplemental drugs. We built mixed-effects logistic regression models to describe differences between drug choice based on induction and recovery times, capture method, and individual variation. Several models were competing, including our null model, which suggests that BAM and NalMed-A are comparable based on the parameters we evaluated. Supplemental drug administration was more frequently needed in NalMed-A immobilizations (21.2%) than in BAM immobilizations (9.0%). Overall, we found minor differences between BAM and NalMed-A, both of which appear to be effective for immobilizing elk in both free-darting and Clover trapping scenarios when performing moderately invasive, minimally painful procedures on free-ranging elk.

Pennsylvania↗

USGS2024

Differential effects of chewing lice on body condition across host age and sex in Rough-legged Hawks (Buteo Lagopus)

Chewing lice infesting avian hosts can significantly affect host health and fitness. Here, we present quantitative data on host body condition and louse abundance observed from 121 Rough-legged Hawks ( Buteo lagopus ) sampled across the North American nonbreeding range. Among hawks examined, louse prevalence was 71%, with a mean abundance and intensity of 9.1 and 12.8 lice, respectively. We identified lice as Craspedorrhynchus sp., either Craspedorrhynchus dilatatus or Craspedorrhynchus taurocephalus , dependent on future taxonomic revision of the genus. Female and juvenile hawks had greater louse intensity and prevalence compared with male and adult hawks, respectively. Host body condition, measured as a breast muscle score (keel score), was negatively correlated with louse abundance after controlling for host age and sex. Possible explanations for these patterns include the following: sex-biased louse transfer between adults and nestlings, when female nestlings experience increased transfer loads; body size differences between males and females, when females are larger than males in each life stage; and preening limitations in females and juveniles, when both spend more time hunting and less time preening relative to adult males. Our results corroborate previous studies suggesting that the primary sources of intraspecific variation in louse abundance are host body size and preening limitations.

Journal of Wildlife Diseases↗

USGS2024

Antibodies to influenza A virus in Lesser (Aythya affinis) and Greater Scaup (Aythya marila) in the USA

Scaup, including both Lesser and Greater ( Aythya affinis and Aythya marila , respectively), are a grouping of populous and widespread North American diving ducks. Few influenza type A viruses (IAV) have been reported from these species despite a high prevalence of antibodies to IAV being reported. Existing virologic and serologic data indicate that IAV infection routinely occurs in scaup, yet it is unknown which IAV subtypes are linked to these infections. In this study, we aimed to gain a more complete picture of IAV natural history in Lesser and Greater Scaup from two coastal flyways in North America in 2015–18 (302 samples from California in the Pacific Flyway and 471 samples from Maryland in the Atlantic Flyway). Low prevalence of active IAV infection was detected by real-time reverse-transcription PCR in Lesser Scaup sampled in Maryland and California (2.8% and 8.1%, respectively). A single IAV (H1N1) was isolated in embryonated chicken eggs from a bird sampled in California. Similarly low levels were observed in Greater Scaup in California (3.3%). Antibodies to the nucleoprotein as detected with a commercial blocking ELISA were observed in all species and flyway combinations. Antibody seroprevalence estimates were higher in adult Lesser Scaup than in juveniles at both the ≤0.5 ( P <0.001, z=–3.582) and ≤0.7 serum-sample-to-negative-control absorbance thresholds ( P =0.003, z=–2.996). Neutralizing antibodies to H1–H12, H14, and H15 were detected using a microtiter virus neutralization assay, with the highest prevalence of antibodies against H1 (38%), H6 (36%), and H11 (35%). The high prevalence of antibodies to IAV and evidence of previous exposure to numerous subtypes are consistent with a high level of population immunity and a low prevalence of infection. These results must be interpreted in the context of season (winter sampling), as results may vary with the annual influx of naïve juvenile birds.

California, Maryland↗

USGS2025

Myiasis infection by the toad fly (Lucilia bufonivora; Calliphoidae) in amphibians in Montana, USA

Toad flies in the genus Lucilia (previously referred to as Bufolucilia spp.) parasitize and cause myiasis in several amphibian species in North America. From 2019 to 2022, we documented Lucilia bufonivora infections in post-metamorphic western toads (Anaxyrus boreas ) during amphibian surveys in four wetlands in Glacier National Park, Montana, US. We found nine infected adult toads in 2019, seven infected adults in 2020, one infected juvenile in 2021, and five infected adults plus one infected juvenile in 2022. We also captured Columbia spotted frogs ( Rana luteiventris ) during these same surveys but detected no infections. Only one of the four wetlands had infected toads in 2019, despite their proximity and hydrologic connectivity, but two of these wetlands had infections in 2020, and a third had a single infection in 2021. The same three of four wetlands had infections in 2022. In 2008, a similar parasitic infection in one western toad had been noted at the same wetland as in 2019. That toad had been captured again two years later without signs of infection.

Montana↗

USGS2025

Highly pathogenic avian influenza virus H5N1 in double-crested cormorants (Nannopterum auritum) of the Chesapeake Bay, USA

Double-crested Cormorants ( Nannopterum auritum ) have historically exhibited low levels of infection and antibodies to avian influenza virus (AIV). The recent global expansion of clade 2.3.4.4b A/goose/Guangdong/1/1996 highly pathogenic (HP) avian influenza virus H5N1 (HPAI H5N1) has resulted in large-scale mortalities across diverse waterbird taxa including cormorants. We sampled 32 and 29 Double-crested Cormorants breeding in the Chesapeake Bay, US, during the summers of 2023 and 2024, respectively, to assess HPAI H5N1 infection and AIV antibodies. Although no mortality was observed in the area, one bird sampled in 2023 was infected with HPAI H5N1. Additionally, 21/31 individuals in 2023 and 10/25 individuals in 2024 for which sera were collected had AIV antibodies. Based on additional testing using hemagglutination inhibition, virus neutralization, and an enzyme-linked lectin assay, 94 and 100% (2023 and 2024, respectively) of the seropositive birds tested positive for antibodies to both H5 and N1, suggesting previous infection with HPAI H5N1. These results are consistent with survival and limited clinical effects related to HPAI H5N1 infections. Furthermore, these results suggest that population immunity to HPAI H5N1 within the Chesapeake Bay might reduce future infections and potential population impacts should HP H5N1 remain on the landscape, though immunity may be waning across time. Because results are based on a single population, additional testing for both infection and antibodies as well as continued monitoring could enhance understanding of antibody persistence.

Maryland, Virginia↗

USGS2025

Highly pathogenic avian influenza virus exposure and infection in free-ranging bobcats (Lynx rufus) in New York, USA

Highly pathogenic H5N1 influenza A virus (HP H5N1) cases in wild mammals have been increasing globally. Carnivora has been the most affected mammal order; however, the extent of morbidity and mortality in carnivores exposed to HP H5N1 remains undefined. We assessed the presence of antibodies to H5 and N1 in the sera of 16 live-captured bobcats ( Lynx rufus ) in New York State, USA; reported on postcapture outcomes of HP H5N1-exposed bobcats; and reported on a case of HP H5N1 infection in one bobcat. In 2024, 4/16 bobcats (25%) tested positive for antibodies to H5 and N1. Two bobcats were confirmed alive as of November 2024 according to GPS data; the other two were alive as of June 2024, when their GPS collars stopped communicating. Another bobcat, which was negative for HP H5N1 antibodies at capture, died from HP H5N1 infection within 5 wks of capture. Our results provide evidence of bobcats both surviving and succumbing to HP H5N1 infection and highlight the importance of focused health studies paired with monitoring data to better understand exposure, infection, and outcomes for novel pathogens and species.

New York↗

USGS1991