KEY POINTS

  • ACE2 is a key receptor for coronavirus spike protein which mediates COVID-19 infection
  • Researchers say numerous mammalian species can get COVID-19 via their ACE2 receptors
  • They hope that their findings will inspire practices to protect both animal and human health

Human beings aren’t the only species vulnerable during the COVID-19 pandemic. The novel coronavirus can affect several animal species via their ACE2 receptors, found a recent study.

The researchers at the University of California, Davis used genomic analysis to compare ACE2 (angiotensin-converting enzyme -2) — the key cellular receptor for the novel coronavirus in human beings and in 410 different species of animals.

ACE2 is a protein present on the surface of many cells located in organs such as lungs, arteries, kidney and intestines. It is the host cell receptor that is responsible for mediating infection by the novel coronavirus. ACE2 acts as a functional receptor for the spike protein of SARS-CoV-2. There are 25 amino acids that code for the ACE2 protein in human beings.

Using genomic analysis, the researchers used these 25 amino acid sequences of the receptor to find out how many of these amino acids were present in the ACE2 protein of other species.

"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," said the study’s first author, Joana Damas, first author for the paper and a postdoctoral research associate at UC Davis.

The researchers believe that their findings will provide an important starting point for identifying susceptible and threatened animal species that might be at risk of COVID-19.

“We hope it inspires practices that protect both animal and human health during the pandemic,” said Harris Lewin, co-author for the study and a distinguished professor of evolution and ecology at UC Davis.

COVID-19 risks among different animal species

  • Critically endangered animals like the Western Lowland gorilla, Northwestern white-cheeked gibbon and Sumatran Orangutan are at a very high risk via their ACE2 receptors
  • Marine mammals including bottlenose dolphins, gray whales and Chinese hamsters are flagged as high risk
  • Domestic animals like cats, sheep and cattle are at a medium risk
  • Other animals like dogs, horses and pigs were found to have a lower risk

In the documented COVID-19 cases in cats, dogs, mink hamsters and other animals, the novel coronavirus might be using the ACE2 receptors or any other receptors to gain access to the host animal cells.

The researchers identified 410 unique vertebrate species with ACE2 receptors and among them were 252 mammals, 72 birds, 65 fishes, 17 reptiles and 4 amphibians. They also predicted that the species which had the highest propensity for the coronavirus spike protein binding to ACE2 receptor will have a high probability of becoming infected by the novel coronavirus and might be potential intermediate hosts for disease transmission.

Due to the potential of COVID-19 transmission from humans to animals and vice versa, national Zoos have strengthened programs to protect animals.

The first canine in South Carolina to test positive for COVID-19 was a dog in Charleston County last month. 

The novel coronavirus originated in the animal kingdom and jumped to humans Representational image of the novel coronavirus. Photo: Centers for Disease Control and Prevention / Handout