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1. Experimental Susceptibility of North American Raccoons (Procyon lotor) and Striped Skunks (Mephitis mephitis) to SARS-CoV-2

   https://doi.org/10.3389/fvets.2021.715307  

   Francisco, Raquel ; Hernandez, Sonia M. ; Mead, Daniel G. ; Adcock, Kayla G. ; Burke, Sydney C. ; Nemeth, Nicole M. ; Yabsley, Michael J. ( January 2022 , Frontiers in Veterinary Science)

   Recent spillback events of SARS-CoV-2 from humans to animals has raised concerns about it becoming endemic in wildlife. A sylvatic cycle of SARS-CoV-2 could present multiple opportunities for repeated spillback into human populations and other susceptible wildlife. Based on their taxonomy and natural history, two native North American wildlife species —the striped skunk ( Mephitis mephitis ) and the raccoon ( Procyon lotor) —represent a high likelihood of susceptibility and ecological opportunity of becoming infected with SARS-CoV-2. Eight skunks and raccoons were each intranasally inoculated with one of two doses of the virus (10 3 PFU and 10 5 PFU) and housed in pairs. To evaluate direct transmission, a naïve animal was added to each inoculated pair 48 h post-inoculation. Four control animals of each species were handled like the experimental groups. At predetermined intervals, we collected nasal and rectal swabs to quantify virus shed via virus isolation and detect viral RNA via rRT-PCR and blood for serum neutralization. Lastly, animals were euthanized at staggered intervals to describe disease progression through histopathology and immunohistochemistry. No animals developed clinical disease. All intranasally inoculated animals seroconverted, suggesting both species are susceptible to SARS-CoV-2 infection. The highest titers in skunks and raccoons weremore »1:128 and 1:64, respectively. Low quantities of virus were isolated from 2/8 inoculated skunks for up to day 5 post-inoculation, however no virus was isolated from inoculated raccoons or direct contacts of either species. Neither species had gross lesions, but recovering mild chronic pneumonia consistent with viral insult was recorded histologically in 5/8 inoculated skunks. Unlike another SARS-CoV-2 infection trial in these species, we detected neutralizing antibodies in inoculated raccoons; thus, future wildlife serologic surveillance results must be interpreted with caution. Due to the inability to isolate virus from raccoons, the lack of evidence of direct transmission between both species, and low amount of virus shed by skunks, it seems unlikely for SARS-CoV-2 to become established in raccoon and skunk populations and for virus to spillback into humans. Continued outbreaks in non-domestic species, wild and captive, highlight that additional research on the susceptibility of SARS-CoV-2 in wildlife, especially musteloidea, and of conservation concern, is needed.« less
2. Habitat loss for black flying foxes and implications for Hendra virus

   https://doi.org/10.1007/s10980-023-01642-w  

   Baranowski, Kelsee ; Bharti, Nita ( April 2023 , Landscape Ecology)

   Environmental change impacts natural ecosystems and wildlife populations. In Australia, native forests have been heavily cleared and the local emergence of Hendra virus (HeV) has been linked to land-use change, winter habitat loss, and changing bat behavior.

   We quantified changes in landscape factors for black flying foxes (Pteropus alecto), a reservoir host of HeV, in sub-tropical Queensland, Australia from 2000–2020. We hypothesized that native winter habitat loss and native remnant forest loss were greatest in areas with the most human population growth.

   We measured the spatiotemporal change in human population size and native ‘remnant’ woody vegetation extent. We assessed changes in the observedP. alectopopulation and native winter habitats in bioregions whereP. alectoare observed roosting in winter. We assessed changes in the amount of remnant vegetation across bioregions and within 50 km foraging buffers around roosts.

   Human populations in these bioregions grew by 1.18 M people, mostly within 50 km foraging areas around roosts. Remnant forest extent decreased overall, but regrowth was observed when policy restricted vegetation clearing. Winter habitats were continuously lost across all spatial scales. Observed roost counts ofP. alectodeclined.

   Native remnant forest loss and winter habitat loss were not directly linked to spatial human population growth. Rather, most remnant vegetationmore »was cleared for indirect human use. We observed forest loss and regrowth in response to state land clearing policies. Expanded flying fox population surveys will help better understand how land-use change has impactedP. alectodistribution and Hendra virus spillover.

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3. From Protein to Pandemic: The Transdisciplinary Approach Needed to Prevent Spillover and the Next Pandemic

   https://doi.org/10.3390/v13071298  

   Plowright, Raina K. ; Hudson, Peter J. ( July 2021 , Viruses)

   Pandemics are a consequence of a series of processes that span scales from viral biology at 10−9 m to global transmission at 106 m. The pathogen passes from one host species to another through a sequence of events that starts with an infected reservoir host and entails interspecific contact, innate immune responses, receptor protein structure within the potential host, and the global spread of the novel pathogen through the naive host population. Each event presents a potential barrier to the onward passage of the virus and should be characterized with an integrated transdisciplinary approach. Epidemic control is based on the prevention of exposure, infection, and disease. However, the ultimate pandemic prevention is prevention of the spillover event itself. Here, we focus on the potential for preventing the spillover of henipaviruses, a group of viruses derived from bats that frequently cross species barriers, incur high human mortality, and are transmitted among humans via stuttering chains. We outline the transdisciplinary approach needed to prevent the spillover process and, therefore, future pandemics.
4. Epidemiology and biology of a herpesvirus in rabies endemic vampire bat populations

   https://doi.org/10.1038/s41467-020-19832-4  

   Griffiths, Megan E. ; Bergner, Laura M. ; Broos, Alice ; Meza, Diana K. ; Filipe, Ana da Silva ; Davison, Andrew ; Tello, Carlos ; Becker, Daniel J. ; Streicker, Daniel G. ( November 2020 , Nature Communications)

   Rabies is a viral zoonosis transmitted by vampire bats across Latin America. Substantial public health and agricultural burdens remain, despite decades of bats culls and livestock vaccinations. Virally vectored vaccines that spread autonomously through bat populations are a theoretically appealing solution to managing rabies in its reservoir host. We investigate the biological and epidemiological suitability of a vampire bat betaherpesvirus (DrBHV) to act as a vaccine vector. In 25 sites across Peru with serological and/or molecular evidence of rabies circulation, DrBHV infects 80–100% of bats, suggesting potential for high population-level vaccine coverage. Phylogenetic analysis reveals host specificity within neotropical bats, limiting risks to non-target species. Finally, deep sequencing illustrates DrBHV super-infections in individual bats, implying that DrBHV-vectored vaccines might invade despite the highly prevalent wild-type virus. These results indicate DrBHV as a promising candidate vector for a transmissible rabies vaccine, and provide a framework to discover and evaluate candidate viral vectors for vaccines against bat-borne zoonoses.
5. Environmental reservoir dynamics predict global infection patterns and population impacts for the fungal disease white-nose syndrome

   https://doi.org/10.1073/pnas.1914794117  

   Hoyt, Joseph R. ; Langwig, Kate E. ; Sun, Keping ; Parise, Katy L. ; Li, Aoqiang ; Wang, Yujuan ; Huang, Xiaobin ; Worledge, Lisa ; Miller, Helen ; White, J. Paul ; et al ( March 2020 , Proceedings of the National Academy of Sciences)

   Disease outbreaks and pathogen introductions can have significant effects on host populations, and the ability of pathogens to persist in the environment can exacerbate disease impacts by fueling sustained transmission, seasonal epidemics, and repeated spillover events. While theory suggests that the presence of an environmental reservoir increases the risk of host declines and threat of extinction, the influence of reservoir dynamics on transmission and population impacts remains poorly described. Here we show that the extent of the environmental reservoir explains broad patterns of host infection and the severity of disease impacts of a virulent pathogen. We examined reservoir and host infection dynamics and the resulting impacts of Pseudogymnoascus destructans , the fungal pathogen that causes white-nose syndrome, in 39 species of bats at 101 sites across the globe. Lower levels of pathogen in the environment consistently corresponded to delayed infection of hosts, fewer and less severe infections, and reduced population impacts. In contrast, an extensive and persistent environmental reservoir led to early and widespread infections and severe population declines. These results suggest that continental differences in the persistence or decay of P. destructans in the environment altered infection patterns in bats and influenced whether host populations were stable or experiencedmore »severe declines from this disease. Quantifying the impact of the environmental reservoir on disease dynamics can provide specific targets for reducing pathogen levels in the environment to prevent or control future epidemics.« less