Genomic analysis reveals that many animal species may be vulnerable to SARS-CoV-2 infection

Humans are not the only species that have a potential threat from SARS-CoV-2, the new coronavirus that causes COVID-19, according to a new study from the University of California, Davis.

An international team of scientists used genomic analysis to compare the main cellular receptor for the virus in humans – angiotensin-converting enzyme-2, like ACE2 – in 410 different types of vertebrae, including birds, fish, amphibians, reptiles and mammals.

ACE2 is normally found on many different types of cells and tissues, including epithelial cells in the nose, mouth and lungs. In humans, 25 amino acids of the ACE2 protein are important for the virus to bind and enter cells.

The researchers used these 25 amino acid sequences of the ACE2 protein, and modeled its predicted protein structure along with the SARS-CoV-2 spike protein, to assess how many of these amino acids in the ACE2 protein are of different species .

“Animals with all 25 amino acid residues corresponding to human protein are predicted to be at the highest risk for SARS-CoV-2 via ACE2,” said Joana Damas, first author of the paper and a postdoctoral fellow at UC Davis. “The risk is predicted to decrease the more the ACE2-binding residues of the species differ from humans.”

About 40 percent of the species potentially susceptible to SARS-CoV-2 are classified as “endangered” by the International Union for Conservation of Nature and may be particularly vulnerable to human-to-animal transmission. The study was published Aug. 21 in the Procedures of the National Academy of Sciences.

“The data provide an important starting point for identifying vulnerable and endangered animal populations at risk for SARS-CoV-2 infection,” said Harris Lewin, lead author of the study and a distinguished professor of evolution and ecology at UC Davis. . “We hope it inspires practices that protect both animal and human health during the pandemic.”

Endangered species predict to be at risk

Several critically endangered primate species, such as the Western lowland gorilla, Sumatran orangutan, and Northern white-cheeked gibbon, are predicted to be at high risk for infection by SARS-CoV-2 through their ACE2 receptor.

Other high-risk animals include marine mammals such as gray whales and bottlenose dolphins, such as Chinese hamsters.

Pets such as cats, cattle and sheep found a medium risk, and dogs, horses and barges found a low risk for ACE2 binding. How this relates to infection and disease risk should be determined by future studies, but for those species that have known data on infectivity, the correlation is high.

In documented cases of SARS-COV-2 infection in mink, cats, dogs, hamsters, lions and tigers, the virus may use ACE2 receptors or they may use receptors other than ACE2 to gain access to host cells. Lower propensity for binding could translate to lower propensity for infection, than lower ability for infection to spread in an animal or between once established animals.

Because of the potential for animals to contract the new human coronavirus, and vice versa, institutions including the National Zoo and the San Diego Zoo, both of which have contributed genomic material to the study, have strengthened programs to benefit both animals and to protect people.

“Zoonotic diseases and how to prevent human-to-animal transmission is not a new challenge for zoos and animal care professionals,” said co-author Klaus-Peter Koepfli, senior research scientist at Smithsonian-Mason School of Conservation and former conservation biologist with the Smithsonian Institute for Conservation Biology Institute for Species Survival and Center for Conservation Genomics. “With this new information, we can concentrate our efforts and plan to keep animals and people safe.”

The authors argue for caution against over-interpreting the predicted animal risks based on the calculation results, noting that the actual risks can only be confirmed with additional experimental data. The list of animals can be found here.

Research has shown that the immediate ancestor of SARS-CoV-2 probably originated in some kind of bat. Bats were found at very low risk to contract the new coronavirus through their ACE2 receptor, which is consistent with actual experimental data.

Whether batjes transmitted the new coronavirus directly to humans, or whether it passed through an intermediate host, is not yet known, but the study supports the idea that one or more intermediate hosts were involved. The data set researchers at zero on what species may have served as an intermediate host in the wild, and support efforts to control a future outbreak of SARS-CoV-2 infection in human and animal populations.