COVID-19 has wreaked havoc for months across the planet, sickening nearly 24 million people and claiming more than 800,000 lives (and counting). However, humans are not the only species susceptible to the new coronavirus, dubbed SARS-CoV-2, which causes COVID-19, scientists say.
Cases have been reported of pets, including cats and dogs, testing positive for the virus in recent months, but many other animals may also be at risk, according to an international team of experts who analyzed genomes to compare the virus' main cell receptors. in humans (angiotensin converting enzyme 2, or ACE2) in 410 different species of vertebrates, including birds, fish, amphibians, reptiles, and mammals.
ACE2 acts as a receptor on various types of cells and tissues, including epithelial cells in the nose, mouth, and lungs. The coronavirus exploits 25 amino acids of the receptor protein to adhere to and enter cells in humans.
This means that animals whose cells have all 25 amino acid residues that match human protein have the highest risk of contracting SARS-CoV-2, say the scientists, who published their findings in a paper. "The risk is predicted to decrease the more ACE2-binding residues differ from the human species," says Joana Damas, a postdoctoral research associate at the University of California, Davis, who was the first author of the study.
“Among the species that we find most at risk of infection by SARS-CoV-2 are wildlife and endangered species. These species represent an opportunity for the spread of SARS-CoV-2 from humans to other susceptible animals, ”Damas and colleagues write.
In total, about 40% of the species that may be susceptible to SARS-CoV-2 are listed as "threatened" by the International Union for Conservation of Nature (IUCN). They include critically endangered primates such as the western lowland gorilla, the Sumatran orangutan, and the northern white-cheeked gibbon.
This means that human contact with these animals, both in zoos and in the wild, must be eliminated or carried out with safety measures that ensure that the virus does not spread to non-human hosts. Just as we contracted the virus directly from animals, probably bats, we can transmit it to other animals, including primates.
"Zoonotic diseases and how to prevent human-to-animal transmission is not a new challenge for zoos and animal care professionals," says Klaus-Peter Koepfli, principal research scientist at the Smithsonian-Mason School of Conservation. "This new information allows us to focus our efforts and plan accordingly to keep animals and humans safe."
However, scientists caution that more experimental data is needed to confirm that the virus can make primates like gorillas and orangutans sick. "Given the limited infectivity data for the species studied, we urge caution not to over-interpret the predictions of the present study," they write.