New research confirms COVID-19 can infect at least 26 mammals, including domesticated ones like dogs and cats - increasing the number of ways by which people can become infected.
The vulnerability of mammals to severe acute respiratory syndrome coronavirus 2, the virus that causes COVID-19, was revealed in a computational study published in the online peer-reviewed open access scientific journal Scientific Reports.
The study says SARS-CoV-2 might infect domestic cats, dogs, mink, lions and tigers, as well as ferrets and macaques. On the other hand, most birds, fish and reptiles don't appear to be at risk of infection.
Study lead author Professor Christine Orengo from the University College London said researchers wanted to look beyond just the animals that had been studied experimentally to see which might be at risk of infection and would warrant further investigation and monitoring.
"The animals we identified may be at risk of outbreaks that could threaten endangered species or harm the livelihoods of farmers," Orengo said.
"The animals might also act as reservoirs of the virus, with the potential to reinfect humans later on, as has been documented on mink farms."
Study joint author Professor Joanne Santini, also from University College London, said it might be important to employ hygiene measures when dealing with animals. These measures must be "similar to the behaviors we've all been learning this year to reduce transmission - and for infected people to isolate from animals as well as from other people."
The team's findings mostly agree with experiments conducted in living animals. The large study modeled how the virus might infect different animals' cells. Researchers investigated how the increase in proteins present in victims can interact with the ACE2 protein it attaches to when it infects people.
The study looked at whether mutations in the ACE2 protein in 215 different animals might reduce the stability of the binding complex between the virus protein and host protein.
Binding to the ACE2 protein enables the virus to gain entry into host cells. Other research has shown that while it might be possible for the virus to infect animals via another pathway, this outcome is unlikely based on current evidence.
What the evidence shows is the inability of the virus to infect an animal if it can't form a stable binding complex with ACE2.
Researchers performed more detailed structural analyses for some animals to better understand how infection risks differ by species. By comparing their findings with other data, they came up with thresholds to predict which animals were at risk and which ones most likely can't be infected.
Santini warned that to protect animals, as well as to protect people, from getting COVID-19 from animals, "we need large-scale surveillance of animals, particularly pets and farm animals, to catch cases or clusters early on while they're still manageable."
