Geology topics

Sean Nashold

Publications and source records attributed to Sean Nashold.

9 recordsLinked to original sources

USGS2024

Little brown bats (Myotis lucifugus) are resistant to SARS-CoV-2 infection

It has been proposed that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that spread through human populations as a pandemic originated in Asian bats. There is concern that infected humans could transmit the virus to native North American bats; therefore, the susceptibility of several North American bat species to the pandemic virus has been experimentally assessed. Big brown bats ( Eptesicus fuscus ) were shown to be resistant to infection by SARS-CoV-2, whereas Mexican free-tailed bats ( Tadarida brasiliensis ) became infected and orally excreted moderate amounts of virus for up to 18 d postinoculation. Little brown bats ( Myotis lucifugus ) frequently contact humans, and their populations are threatened over much of their range due to white-nose syndrome, a fungal disease that is continuing to spread across North America. We experimentally challenged little brown bats with SARS-CoV-2 to determine their susceptibility and host potential and whether the virus presents an additional risk to this species. We found that this species was resistant to infection by SARS-CoV-2. These findings provide reassurance to wildlife rehabilitators, biologists, conservation scientists, and the public at large who are concerned with possible transmission of this virus to threatened bat populations.

Journal of Wildlife Diseases↗

USGS2023

Experimental infection of Mexican free-tailed bats (Tadarida brasiliensis) with SARS-CoV-2

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus is thought to have originated in wild bats from Asia, and as the resulting pandemic continues into its third year, concerns have been raised that the virus will expand its host range and infect North American wildlife species, including bats. Mexican free-tailed bats ( Tadarida brasiliensis ) live in large colonies in the southern United States, often in urban areas and, as such, could be exposed to the virus from infected humans. We experimentally challenged wild T. brasiliensis with SARS-CoV-2 to determine the susceptibility, reservoir potential, and population impacts of infection in this species. Of 10 bats oronasally inoculated with SARS-CoV-2, 5 became infected and orally excreted moderate amounts of virus for up to 18 days postinoculation. These five subjects all seroconverted and cleared the virus before the end of the study with no obvious clinical signs of disease. We additionally found no evidence of viral transmission to uninoculated subjects. These results indicate that while T. brasiliensis are susceptible to SARS-CoV-2 infection, infection of wild populations of T. brasiliensis would not likely cause mortality. However, the transmission of SARS-CoV-2 from T. brasiliensis to or from humans, or to other animal species, is a possibility requiring further investigation to better define.

mSphere↗

USGS2021

Highly pathogenic avian influenza virus H5N2 (Clade 2.3.4.4) challenge of mallards age appropriate to the 2015 midwestern poultry outbreak

Background The 2015 highly pathogenic avian influenza virus (HPAIV) H5N2 clade 2.3.4.4 outbreak in upper midwestern U.S. poultry operations was not detected in wild birds to any great degree during the outbreak, despite wild waterfowl being implicated in the introduction, reassortment, and movement of the virus into North America from Asia. This outbreak led to the demise of over 50 million domestic birds and occurred mainly during the northward spring migration of adult avian populations. Objectives There have been no experimental examinations of the pathogenesis, transmission, and population impacts of this virus in adult wild waterfowl with varying exposure histories—the most relevant age class. Methods We captured, housed, and challenged adult wild mallards ( Anas platyrhynchos ) with HPAIV H5N2 clade 2.3.4.4 and measured viral infection, viral excretion, and transmission to other mallards. Results All inoculated birds became infected and excreted moderate amounts of virus, primarily orally, for up to 14 days. Cohoused, uninoculated birds also all became infected. Serological status had no effect on susceptibility. There were no obvious clinical signs of disease, and all birds survived to the end of the study (14 days). Conclusions Based on these results, adult mallards are viable hosts of HPAIV H5N2 regardless of prior exposure history and are capable of transporting the virus over short and long distances. These findings have implications for surveillance efforts. The capture and sampling of wild waterfowl in the spring, when most surveillance programs are not operating, are important to consider in the design of future HPAIV surveillance programs.

Wisconsin↗

USGS2021

Experimental challenge of a North American bat species, big brown bat (Eptesicus fuscus), with SARS-CoV-2

The recently emerged novel coronavirus, SARS‐CoV‐2, is phylogenetically related to bat coronaviruses (CoVs), specifically SARS‐related CoVs from the Eurasian bat family Rhinolophidae. As this human pandemic virus has spread across the world, the potential impacts of SARS‐CoV‐2 on native North American bat populations are unknown, as is the ability of North American bats to serve as reservoirs or intermediate hosts able to transmit the virus to humans or to other animal species. To help determine the impacts of the pandemic virus on North American bat populations, we experimentally challenged big brown bats ( Eptesicus fuscus ) with SARS‐CoV‐2 under BSL‐3 conditions. We inoculated the bats both oropharyngeally and nasally, and over the ensuing three weeks, we measured infectivity, pathology, virus concentrations in tissues, oral and rectal virus excretion, virus transmission, and clinical signs of disease. We found no evidence of SARS‐CoV‐2 infection in any examined bat, including no viral excretion, no transmission, no detectable virus in tissues, and no signs of disease or pathology. Based on our findings, it appears that big brown bats are resistant to infection with the SARS‐CoV‐2. The potential susceptibility of other North American bat species to SARS‐CoV‐2 remains to be investigated.

Transboundary and Emerging Diseases↗

USGS2020

Serosurvey of coyotes (Canis latrans), foxes (Vulpes vulpes, Urocyon cinereoargenteus) and raccoons (Procyon lotor) for exposure to influenza A viruses in the USA

We tested coyote ( Canis latrans ), fox ( Urocyon cinereoargenteus , Vulpes vulpes ), and raccoon ( Procyon lotor ) sera for influenza A virus (IAV) exposure. We found 2/139 samples (1 coyote, 1 raccoon) had IAV antibodies and hemagglutination inhibition assays revealed the antibodies to the 2009/2010 H1N1 human pandemic virus or to the 2007 human seasonal H1N1 virus.

Wildlife Disease↗

USGS2019

Avian influenza virus prevalence in marine birds is dependent on ocean temperatures

Waterfowl and shorebirds are the primary hosts of influenza A virus (IAV), however, in most surveillance efforts, large populations of birds are not routinely examined; specifically marine ducks and other birds that reside predominately on or near the ocean. We conducted a long-term study sampling sea ducks and gulls in coastal Maine for IAV and found a virus prevalence (1.7%) much lower than is typically found in freshwater duck populations. We found wide year-to-year variation in virus detection in sea ducks and that the ocean water temperature was an important factor affecting IAV prevalence. In particular, the ocean temperature that occurred 11 d prior to collecting virus positive samples was important while water temperature measured concurrently with host sampling had no explanatory power for viral detection. We also experimentally showed that IAV is relatively unstable in sea water at temperatures typically found during our sampling. This represents the first report of virus prevalence and actual environmental data that help explain the variation in marine IAV transmission dynamics.

Maine↗

USGS2019

Aerosol transmission of gull-origin Iceland subtype H10N7 influenza A virus in ferrets

Subtype H10 influenza A viruses (IAVs) have been recovered from domestic poultry and various aquatic bird species, and sporadic transmission of these IAVs from avian species to mammals (i.e., human, seal, and mink) are well documented. In 2015, we isolated four H10N7 viruses from gulls in Iceland. Genomic analyses showed four gene segments in the viruses were genetically associated with H10 IAVs that caused influenza outbreaks and deaths among European seals in 2014. Antigenic characterization suggested minimal antigenic variation among these H10N7 isolates and other archived H10 viruses recovered from human, seal, mink, and various avian species in Asia, Europe, and North America. Glycan binding preference analyses suggested that, similar to other avian-origin H10 IAVs, these gull-origin H10N7 IAVs bound to both avian-like alpha 2,3-linked sialic acids and human-like alpha 2,6-linked sialic acids. However, when the gull-origin viruses were compared with another Eurasian avian–origin H10N8 IAV, which caused human infections, the gull-origin virus showed significantly higher binding affinity to human-like glycan receptors. Results from ferret experiment demonstrated that a gull-origin H10N7 IAV replicated well in turbinate, trachea, and lung, but replication was most efficient in turbinate and trachea. This gull-origin H10N7 virus can be transmitted between ferrets through the direct contact and aerosol routes, without prior adaptation. Gulls share their habitat with other birds and mammals, and have frequent contact with humans; therefore, gull-origin H10N7 IAVs could pose a risk to public health. Surveillance and monitoring of these IAVs at the wild bird-human interface should be continued.

Journal of Virology↗

USGS2019

Inactivation of viable surrogates for the select agents virulent Newcastle disease virus and highly pathogenic avian influenza virus using either commercial lysis buffer or heat

Introduction: Federal Select Agent Program regulations require laboratories to document a validated procedure for inactivating select agents prior to movement outside registered space. Avian influenza viruses and virulent Newcastle disease virus (vNDV) are cultured in chicken amnio-allantoic fluid (AAF), but the efficacy of commercial lysis buffers to inactivate viruses in protein-rich media has not been documented. Objectives: We assesses the efficacy of MagMAX™ lysis buffer for inactivating highly pathogenic avian influenza virus (HPAIV) and vNDV in chicken AAF and confirm the inactivation of avian influenza in serum using heat. Methods: Low pathogenic avian influenza virus (LPAIV) and avian paramyxovirus subtype-1 (APMV-1) were incubated with lysis buffer and tested for viability. Known viable LPAIV and APMV-1 RNA was extracted from AAF using MagMAX™-96 AI/ND Viral RNA Isolation kit, and the eluate was tested for remaining infectious agent. Finally, inactivation of LPAIV in serum was examined over 3 combinations of temperature and incubation time. Results: MagMAX™ lysis buffer inactivated both LPAIV and APMV-1 in AAF when incubated for 30 minutes at room temperature. The full extraction process eliminated viable virus from the final RNA eluate. LPAIV in serum heated to 70°C for 30 minutes was rendered noninfectious. Conclusion: The ability of a diagnostic laboratory to move samples from one space to another is critical to maintaining biosecurity as well as efficient laboratory workflow. Our study demonstrates a method to ensure the inactivation of viable avian influenza and avian paramyxoviruses in AAF, RNA eluate, and viable avian influenza virus in sera.

Applied Biosafety↗

USGS1998

Preliminary evaluation of a simple in vitro test for the diagnosis of type C botulism in wild birds

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of type C botulinum toxin ( Clostridium botulinum ) in wild birds. This simple, antigen-capture ELISA utilizes polystyrene immunosticks as the solid substrate, chicken antitoxin (IgY) as the coating antibody, rabbit antitoxin as the primary antibody, and peroxidase-labeled goat-anti-rabbit as the secondary antibody. To evaluate the immunostick ELISA as a diagnostic test for avian botulism, known concentrations of toxin were added to heparinized blood collected from healthy birds and tested by both the ELISA and mouse bioassay. Also, blood samples from 236 bird carcasses submitted to the National Wildlife Health Center (NWHC) for cause of death determinations were tested by both procedures. Using ≤ 0.5 ml as the test volume for both procedures, the ELISA was less sensitive, detecting 0.25 ng/ml of toxin compared to 0.12 ng/ml for the mouse bioassay. Using the same volume of test sample for diagnostic submissions (≤ 0.5 ml), the ELISA was positive for 60% of the 149 clinically-diagnosed cases of botulism, whereas the mouse bioassay was positive for 79%. However, we demonstrated that with larger sample volumes (≥ 1.0 ml), the sensitivity of the ELISA may be equivalent or better than the mouse test due to the concentrating effect of the ELISA procedure. These preliminary results suggest that when adequate sample volumes are available, the immunostick ELISA can replace the mouse test for the diagnosis of botulism in wild birds.

Journal of Wildlife Diseases↗