Humans are not the only species facing a potential threat from SARS-CoV-2, the novel coronavirus that causes COVID-19

An international team of scientists used genomic analysis to compare the main cellular receptor for the virus in humans -- angiotensin converting enzyme-2, or ACE2 -- in 410 different species of vertebrates, 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 gain entry into cells.

"Animals with all 25 amino acid residues matching the human protein are predicted to be at the highest risk for contracting SARS-CoV-2 via ACE2" "The risk is predicted to decrease the more the species' ACE2 binding residues differ from humans."

The data provide an important starting point for identifying vulnerable and threatened animal populations at risk of SARS-CoV-2 infection

Endangered species predicted 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 very high risk of infection by SARS-CoV-2 via their ACE2 receptor.

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

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

In documented cases of SARS-COV-2 infection in mink, cats, dogs, hamsters, lions and tigers, the virus may be using 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, or lower ability for the infection to spread in an animal or between animals once established.

Zoonotic diseases and how to prevent human to animal transmission is not a new challenge to zoos and animal care professionals. This new information allows us to focus our efforts and plan accordingly to keep animals and humans safe.