The Zoonomia Project, an initiative by the Broad Institute at Harvard and MIT along with over twenty other academic institutions to catalog the genomic sequence of every mammalian species on Earth, was recently used to discover the effect of COVID-19 on animal species beyond humans.
The study, using genomic analysis, reveals that many animal species may be vulnerable to the SARS-CoV-2 virus. An international team of researchers compared the human cellular receptor angiotensin-converting enzyme-2, or ACE2 in 410 different species of vertebrates, including birds, fish, amphibians, reptiles, and mammals. ACE2 is typically found on cells and tissues in humans found in epithelial cells in the nose, mouth, and lungs. These 25 amino acids of the ACE2 protein allow for the virus to bind and gain entry into cells.
The researchers used these amino acid sequences and modeling of its predicted protein structure together with the SARS-CoV-2 spike protein, to evaluate how many of these amino acids are found in the ACE2 protein of the various species included in the study.
They found that species that had all 25 amino acids that mimicked the human sequence were at high risk for contracting the virus and the further away from having all residuals of ACE2, the lower the risk became. The study, published in the Proceedings of the National Institute of Sciences, reported that 40 percent of the species potentially susceptible to the virus to be classified as threatened and extremely vulnerable to human-to-animal transmission. Graham Hughes of University College Dublin, Kathleen Keough of the University of California, San Francisco, and Corrie Painter and Nicole Persky of the Broad Institute were the other co-first authors of the paper.
Several critically endangered primate species, such as the Western lowland gorilla, Sumatran orangutan, Northern white-cheeked gibbon, marine mammals such as gray whales and bottlenose dolphins, as well as Chinese hamsters are predicted to be at very high risk of infection.
Domestic animals such as cats, cattle, and sheep were found to have medium risk, and dogs, horses, and pigs were found to have a 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.
Because of the potential for animals to contract the novel coronavirus from humans, and vice versa, institutions including the National Zoo and the San Diego Zoo, which both contributed genomic material to the study, have strengthened programs to protect both animals and humans.