COVID-19 Update: Animals at Risk

According to new modeling, 26 animals that are in regular contact with humans may be susceptible to SARS-CoV-2, the virus responsible for COVID-19. The SARS-CoV-2 coronavirus infects human cells by interacting with the ACE2 receptor on the cell surface. This receptor, which allows the virus to enter host cells and infect them, exists in many animals but in different forms that are recognized to varying degrees by the virus. This affinity partly determines vulnerability to the virus. Based on current knowledge, it is possible but unlikely that the virus could infect cells through another mechanism. The ACE2 receptor is therefore the virus’s entry point, which determines whether or not an animal can be infected by the virus. Researchers therefore studied the genetics and structure of the ACE2 protein in 215 different animals to identify mutations that could compromise the stability of the binding complex between the viral protein and the host receptor. The study confirms that great apes (chimpanzees, gorillas, orangutans, and bonobos) are at risk. Their ACE2 receptor appears capable of binding to the virus just as strongly as the human version. But they are not the only ones. The same is true for the receptor in sheep, for example. However, no infection tests have yet been conducted on sheep to confirm that the animal can actually be infected. But that was the goal of the study: to go beyond the experimental infection tests that had been conducted only on certain animals, and to expand the assessment of risks in other species to identify those that would require further research and potential monitoring. Unlike laboratory experiments, computational analyses can be performed automatically and quickly. They would therefore enable large-scale monitoring of animals, particularly pets and farm animals, which are in close contact with humans. It is clear, therefore, that most birds, fish, and reptiles do not appear to be at risk of infection, but that the majority of mammals examined could potentially be at risk. Domestic cats, dogs, minks, lions, tigers, as well as ferrets and macaques, are at risk, and cases have already been confirmed. The results largely align with reported cases of infection. Regarding cats and dogs, which are particularly close to humans, one study took a closer look at their response to the viral infection. Dogs, like cats, can be infected with the virus without, however, showing any clinical symptoms. And while cats do not appear to spread the disease, cats infected with the coronavirus can. Infected cats can transmit the virus to other healthy cats, which develop a strong immune response after infection. But animal owners should not be alarmed. To date, however, no cases of transmission from animals to humans have been reported, and transmission from humans to animals remains rare. It is nevertheless advisable to take precautions around animals if animal owners become infected themselves.