COVID-19 as a zoonotic infection

Abstract

Here we discuss the issues for attributing the new coronavirus infection COVID-19 to zoonoses based on the data on probable origin of the SARS-CoV-2 virus, the possible formation of its reservoir in animals (bats) as well as human susceptibility. Today, the dominant point of view is that the outbreak of COVID-19 arose as a result of the SARS-CoV-2 coronavirus overcoming the interspecies barrier, acquiring ability to infect and spread in human population. Comparative phylogenetic analysis at the molecular level showed that SARS-CoV-2 is genetically closest to bat coronaviruses, particularly to the RmYN02 and RaTG13 strains isolated from the horseshoe bat, a species considered to be the main host of SARSCoV and MERS-CoV coronaviruses. The ability of the SARS-CoV-2 coronavirus to infect various wild animal has been revealed. SARS-CoV-2 has been found in minks on farms in the Netherlands with mortality rates ranging from 1.2 to 2.4%. While infecting rhesus monkeys with the SARS-CoV-2, it resulted in productive infection and detected viremia. Cats have been found to be susceptible hosts for the human SARS-CoV-2 virus. A likely explanation for this lies in the high similarity between the human and feline counterpart of the ACE2 receptor. It has been shown that dogs can become infected but transmit no virus to other animals. To date, over the entire period of the pandemic the World Organization for Animal Health provides no information about cases of human infection transmitted from pets. Thus, there is no evidence that animals play a role in the spread of SARS-CoV-2 among people during the current period of the pandemic. Human outbreaks are caused by human-to-human virus transmission, and based on the currently available information, the risk of spreading COVID-19 from animals is considered low. More research is needed to understand how COVID-19 can affect animals of a wide variety of species and how big might be the risks of infection transmission from them to humans.