A One Health Perspective
Dec 9 2020
After emerging from a bat coronavirus, SARS-COV-2, has caused significant disease in the world population and the COVID-19 pandemic remains ongoing. Since the initial reports of human disease, it has additionally become apparent that the virus can cause disease in numerous other hosts, including domestic and non-domestic felids, laboratory ferrets, and farm-raised minks (Bartlett et al., 2020; Gaudreault et al., 2020; Kim et al., 2020; Molenaar et al., 2020). At present, each of these cases have been in a situation where either there was human involvement or there has been laboratory experimentation.
Despite the global tragedy caused by the COVID-19 pandemic, the WHO still only estimates that a minority of the population has already been exposed. While the hope is to mitigate the risk of COVID-19, including through the use of a vaccine, questions still remain for what SARS-CoV-2 might mean for wildlife species. By comparison, feline coronavirus (FCoV) circulates widely in domestic cat populations, and can result in the systemic disease, feline infectious peritonitis (FIP). One of the most notable cases of FCoV causing disease in a non-domestic felid species was in captive Cheetahs, which resulted in nearly 60% mortality (Heeney et al., 1990). Beyond zoo housed species, several studies have demonstrated FCoV exposure in wild felids, including lions, cheetahs and mountain lions (Foley et al., 2013; Kennedy et al., 2003). While exposure in these species is relatively rare, it does not preclude disease development. For instance, FIP has been documented in a free-ranging Mountain Lion in California (Stephenson et al., 2013). Across any of these species, it remains largely unclear how exposure might have occurred. Suggested exposure mechanisms have included close contact with domestic cats, environmental exposure potentially via feces, or maintenance of the virus in the wild population. Though FCoV is relatively rare in wildlife species, the risk is nonetheless, not zero.
If we consider cats as a compatible host for SARS-CoV-2, it raises the question whether domestic cats might be a conduit to spread SARS-CoV-2 from their owners to wildlife species. With documented cases of cats becoming infected from their owners and with experimental data to show transmission between domestic cats, a larger one-health issue must be considered. Currently, cases of wildlife being infected with SARS-CoV-2 have not been documented. However, as always, absence of evidence is not evidence of absence.
The veterinary community has the potential to help minimize the possibility of wildlife cases of SARS-CoV-2. First, we must continue to follow and promote the CDC guidelines, which recommend avoiding direct contact with household pets if a person is symptomatic. Second, keeping cats indoors can minimize the risk of infectious disease spread, in addition to helping prevent predation, and eliminating the chance of being hit by a car. Currently, there is also investigation regarding a feline vaccine for SARS-CoV-2. With cats being a compatible host for SARS-CoV-2, the vaccine may help prevent morbidity or mortality. However, this vaccine may additionally help halt the onward transmission of SARS-CoV-2 into other species and provide for one health protection, similar to the rabies vaccine. The rabies vaccine protects individual pets, owners, and provides for the greater good of one health. Though SARS-CoV-2 is not nearly as lethal as rabies, the potential for gaining a foothold in wildlife species could be catastrophic for wildlife species and for human health.
The veterinary oath calls for the “promotion of public health.” Despite the stress of the pandemic, our profession has met the challenges of keeping animals healthy and their human counterparts safe. As the future unfolds, our role in helping control the pandemic will continue to be of importance.
Contributed by Alison Stout
References
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