SARS-CoV-2 in cats, dogs, ferrets, and minks: The ACE2 receptor connection
This research sheds light on SARS-CoV-2 transmission between humans and various animals including cats, dogs, ferrets, and farm minks.
In a recent review1 published in the journal Viruses, researchers discussed the potential risks of animal-to-human and human-to-animal transmission of SARS-CoV-2—the virus causing COVID-19 in humans. The researchers focused on cats, dogs, ferrets, and farm minks.
SARS-CoV-2 uses the ACE2 receptor for the virus to enter its host. Twenty-four amino acid residues in human ACE2 are required to bind to SARS-CoV-2’s spike protein. A species with similar amino acid residues would be a susceptible host. Dogs’ and cats’ ACE2 has greater than 50% similarity to human ACE2.1
Cats are more sensitive to SARS-CoV-2 than dogs. Since the start of the pandemic, there have been 126 outbreaks of SARS-CoV-2 reported in cats (67 in the United States)1 and only a few cases in dogs. These animals likely contracted COVID-19 from their infected owners, and subsequently developed respiratory symptoms. Of serum samples collected from cats, 14.7% contained SARS-CoV-2, and of those 10.8% contained viral neutralizing antibodies.1 Only 3.3% of 919 dogs had SARS-CoV-2 neutralizing antibody titers.1 The data shows that it is possible, but not likely, for dogs and cats to acquire COVID from their owners.
Ferrets are highly susceptible to SARS-CoV-2 both naturally and experimentally. SARS-CoV-2 antibodies remained at detectable levels for more than 129 days after the first detection of antibodies.1 Researchers tested lopinavir-ritonavir, hydroxychloroquine sulfate, and emtricitabine-tenofovir as antivirals for COVID in ferrets. Only emtricitabine-tenofovir lowered the virus titers in ferrets.1 Lipoprotein fusion inhibitors were also used in ferrets to completely block transmission.
Farmed minks have also contracted SARS-CoV-2 and are very susceptible. One case of a mink likely transmitting COVID to a human has been reported,1 and in that case, the mink and human were in close contact.
Overall, we should be cautious about infecting pets, cats particularly. Ferrets are a good animal model that is being used to study SARS-CoV-2, and minks are the one animal that has been shown to have the potential to infect humans, but more research is needed.
Ryan Moriarty is a 2022 PharmD candidate at the University of Connecticut.
- Dróżdż M, Krzyżek P, Dudek B, Makuch S, Janczura A, Paluch E. Current state of knowledge about role of pets in zoonotic transmission of SARS-CoV-2. Viruses. 2021;13(6):1149. Published June 16, 2021. doi:10.3390/v13061149