Research to understand SARS-CoV-2 risks for wildlife
Multiple research endeavors at the USGS National Wildlife Health Center are ongoing to help assess the possible impacts of SARS-CoV-2 on wildlife.
Why this matters: Questions remain about the impact SARS-CoV-2, the virus the cause COVID-19 in humans, may have on wildlife including 1) the potential for humans to transmit the virus to North American wildlife, 2) its potential effects on native wildlife populations, and 3) the resultant possibility and consequences of a persistent wildlife reservoir. These research activities are designed to help us better understand these risks.
Experimental SARS-CoV-2 trials in North American bat species
Bats have been identified as a natural reservoir for several severe acute respiratory syndrome (SARS)-like coronaviruses (CoV) (Li et al. 2005). The virus isolated from early human cases during the recent SARS-CoV-2 pandemic most closely resembled a betacoronavirus isolated from Asian horseshoe bats (Rhinolophus sp.). If SARS-CoV-2 spilled from humans to native North American bat populations, it could potentially create a wildlife reservoir and permit reassortment (mixing/rearrangement) with other native bat coronaviruses. Several experimental infection studies are being conducted at the USGS National Wildlife Health Center to evaluate the susceptibility of North American bats to SARS-CoV-2. In the initial trial, big brown bats (Eptesicus fuscus) demonstrated resistance to infection (Hall et al. 2021). Mexican free-tailed bats (Tadarida brasiliensis), contrarily, were susceptible to infection but did not infect co-housed control bats (Hall et al. 2023). Results of an experimental trial with little brown bats (M. lucifugus) are pending laboratory analyses and a trial with pallid bats (Antrozous pallidus) is planned for the fall of 2023.
Coronavirus diversity in North American bats
To assess coronavirus genetic diversity in North American bats, environmental guano samples from 97 summer roosts in sixteen U.S. states (79 counties) and British Columbia, Canada were collected during white-nose syndrome/P. destructans national surveillance by state, federal, tribal, and provincial partners. Sampling was coordinated by the USGS National Wildlife Health Center. Initial evaluation for the presence of the coronavirus RNA-dependent RNA polymerase (RdRp) gene (Hu et al. 2018) yielded a total of 85 presumptive positive samples from 75 individual roosts, out of 119 composite samples analyzed. Further testing via genetic cloning and sequence analysis has so far identified several different alphacoronaviruses in the samples tested. Phylogenetic analyses of the viruses to understand their geographic distribution and associations with the various North American bat species is ongoing. To date neither SARS-CoV-2, nor any other betacoronavirus, has been detected in free-ranging North American bats.
SARS-CoV-2 and black-footed ferrets
The novel coronavirus SARS-CoV-2 is considered a potential threat to black-footed ferrets (Mustela nigripes; BFF), a highly endangered mammal in North America. To assess the safety and effectiveness of commercially available viral proteins to elicit a protective immune response against SARS-CoV-2, researchers from the USGS National Wildlife Health Center, U.S. Fish and Wildlife Service National Black-Footed Ferret Conservation Center, and Colorado State University vaccinated and boosted 15 captive BFF (Leon et al. 2022). The study demonstrated a significant rise in antibodies against SARS-CoV-2 in vaccinated BFF. An experimental challenge study in a second group of captive BFF was completed at Colorado State University to test susceptibility to SARS-CoV-2. Despite viral replication and shedding in the upper respiratory tract for up to seven days post-challenge, no clinical disease or pathologic lesions attributable to viral infection was observed in either vaccinated or un-vaccinated animals. The lack of observed morbidity or mortality suggests SARS-CoV-2 is unlikely to affect wild BFF populations, but infected captive animals pose a potential risk for humans and other animals.
SARS-CoV-2 in Wildlife
Development of SARS-CoV-2 vaccine to support black-footed ferret conservation
Multiple research endeavors at the USGS National Wildlife Health Center are ongoing to help assess the possible impacts of SARS-CoV-2 on wildlife.
Why this matters: Questions remain about the impact SARS-CoV-2, the virus the cause COVID-19 in humans, may have on wildlife including 1) the potential for humans to transmit the virus to North American wildlife, 2) its potential effects on native wildlife populations, and 3) the resultant possibility and consequences of a persistent wildlife reservoir. These research activities are designed to help us better understand these risks.
Experimental SARS-CoV-2 trials in North American bat species
Bats have been identified as a natural reservoir for several severe acute respiratory syndrome (SARS)-like coronaviruses (CoV) (Li et al. 2005). The virus isolated from early human cases during the recent SARS-CoV-2 pandemic most closely resembled a betacoronavirus isolated from Asian horseshoe bats (Rhinolophus sp.). If SARS-CoV-2 spilled from humans to native North American bat populations, it could potentially create a wildlife reservoir and permit reassortment (mixing/rearrangement) with other native bat coronaviruses. Several experimental infection studies are being conducted at the USGS National Wildlife Health Center to evaluate the susceptibility of North American bats to SARS-CoV-2. In the initial trial, big brown bats (Eptesicus fuscus) demonstrated resistance to infection (Hall et al. 2021). Mexican free-tailed bats (Tadarida brasiliensis), contrarily, were susceptible to infection but did not infect co-housed control bats (Hall et al. 2023). Results of an experimental trial with little brown bats (M. lucifugus) are pending laboratory analyses and a trial with pallid bats (Antrozous pallidus) is planned for the fall of 2023.
Coronavirus diversity in North American bats
To assess coronavirus genetic diversity in North American bats, environmental guano samples from 97 summer roosts in sixteen U.S. states (79 counties) and British Columbia, Canada were collected during white-nose syndrome/P. destructans national surveillance by state, federal, tribal, and provincial partners. Sampling was coordinated by the USGS National Wildlife Health Center. Initial evaluation for the presence of the coronavirus RNA-dependent RNA polymerase (RdRp) gene (Hu et al. 2018) yielded a total of 85 presumptive positive samples from 75 individual roosts, out of 119 composite samples analyzed. Further testing via genetic cloning and sequence analysis has so far identified several different alphacoronaviruses in the samples tested. Phylogenetic analyses of the viruses to understand their geographic distribution and associations with the various North American bat species is ongoing. To date neither SARS-CoV-2, nor any other betacoronavirus, has been detected in free-ranging North American bats.
SARS-CoV-2 and black-footed ferrets
The novel coronavirus SARS-CoV-2 is considered a potential threat to black-footed ferrets (Mustela nigripes; BFF), a highly endangered mammal in North America. To assess the safety and effectiveness of commercially available viral proteins to elicit a protective immune response against SARS-CoV-2, researchers from the USGS National Wildlife Health Center, U.S. Fish and Wildlife Service National Black-Footed Ferret Conservation Center, and Colorado State University vaccinated and boosted 15 captive BFF (Leon et al. 2022). The study demonstrated a significant rise in antibodies against SARS-CoV-2 in vaccinated BFF. An experimental challenge study in a second group of captive BFF was completed at Colorado State University to test susceptibility to SARS-CoV-2. Despite viral replication and shedding in the upper respiratory tract for up to seven days post-challenge, no clinical disease or pathologic lesions attributable to viral infection was observed in either vaccinated or un-vaccinated animals. The lack of observed morbidity or mortality suggests SARS-CoV-2 is unlikely to affect wild BFF populations, but infected captive animals pose a potential risk for humans and other animals.