Scientists Still Intend To Find Out If Animals Can Spread SARS-CoV-2

Scientists still intend to find out if animals can spread SARS-CoV-2

Researchers still do not have complete data on the susceptibility of different animal species to coronavirus and the risks of transmission, including interspecies.

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Soon after the coronavirus began to spread around the world, reports of animal cases began to appear in various countries. So, there were cases of infection of cats in Hong Kong, tigers in the New York zoo and minks on farms in the Netherlands. So far, only two cases of animal-to-human transmission of SARS-CoV-2 have been confirmed - in both cases they were farm minks. But as global morbidity declines and restrictions are lifted, the potential risk of human infection from animals that live near us increases. Scientists from different countries are calling for large-scale selection and study of genetic samples of domestic and wild animals, as well as livestock, to assess the degree of this risk, writes Nature.

According to Joanne Santini, a microbiologist at University College London, the virus can spread undetected in some animals. “We just don't have enough data,” says the researcher.

Scientists remind that pathogens often circulate between different species, which makes it difficult to control the spread of viruses. Most likely, the person received SARS-CoV-2 from bats, but the researchers do not know how many animals were involved in the transmission chain. The H1N1 pandemic influenza virus is known to have originated in pigs, transmitted to humans and spread throughout the world, and then returned to pigs and continues to circulate.

At least twelve different animals are known to be susceptible to coronavirus, including domestic dogs and cats, lions, tigers and farm minks. This means, for example, that like all animals of the weasel family - minks, weasels, badgers, wolverines, martens - can be potentially susceptible to coronavirus and transmit it to humans. But until now, no one has tested this possibility.

Laboratory experiments have confirmed susceptibility to the virus in hamsters, rabbits and monkeys, while pigs, ducks and chickens cannot become infected. However, no one has conducted similar studies on cows, sheep, horses or other livestock.

"If SARS-CoV-2 appears in wild animals that have close contact with livestock, the likelihood of interspecific transmission may increase," says Ohio State University in Wooster virologist Linda Saif. The fact that an animal can infect another animal does not mean the risk of infection for humans, she said. But to assess this risk, researchers must study how much of the virus is shed by different species of animals and how much is needed to infect humans.

At the moment, different countries are planning to study various animal species for susceptibility to coronavirus. For example, Asisa Volz, a veterinary virologist at the University of Veterinary Medicine Hannover, intends to find out if cats are spreading the infection in a nursing home in Bavaria, whose patients continue to get sick despite strict quarantine. One of the cats in the boarding house was found to have traces of coronavirus RNA, that is, in theory, it could spread the infection.

Arjan Stegeman, a veterinary epidemiologist at Utrecht University, also plans to test cats living with humans infected with COVID-19 in the Netherlands. "If it turns out that cats can transmit the virus to humans, the spread of the infection will be more difficult to control," says the scientist.