9th April 2020
As the world struggles to combat the deadly coronavirus, virologists have pointed out concerns regarding the way it spreads, specifically future animal hosts. Experts say that the virus can find a new reservoir of hosts as a result of humans spreading it around the world. Ralph Baric, a virologist at the University of North Carolina, warns that countries need to take this possibility into consideration as the epidemics wind down.
Coronaviruses are notoriously unstable, continuously mutating to the point whereby bats can host thousands of types without succumbing to the illness. That variability together with the ability to jump to new species by either adapting to a new host or without any change is a cause for major concern. The virus has also been known to infect mammals (dogs, cats, cattle, pigs, bats, and pangolins) as well as birds such as chicken. For this reason, virologists are working to predict which species will act as a new reservoir for the virus.
By using 3D computer modeling, virologists can predict potential host species by analyzing which animals have the recently discovered ACE2 protein receptor, which the virus binds to on an animal cell to cause infection. A study using this method in March 2020 identifies cows, buffalo, goats, sheep, pigeons and civets as potential hosts.
Baric's lab is taking a different approach to this method by exposing different animal cells to the virus to see which species can become infected. The next step in their research would then be to do tests with live animals in a controlled environment and eventually surveying wildlife in their natural environments to account for thee frequent host shifting coronaviruses are prone to, according to Baric. The Friedrich-Loeffler Institut, the German government's research organization focused on animal health and welfare is also conducting similar research.
Disease ecologist Peter Daszak, president of the EcoHealth Alliance predicts that animals that humans spend the most time with are most likely to get infected. Virologists, however, say that there is no certainty that the virus will colonize and persist in a new species as other factors come into play such as whether the new host will be capable of re-introducing the virus to humans. Another factor virologists have had to consider is if livestock become infected, would the symptoms be identifiable enough to contain the outbreak, or could the symptoms be non-specific and thus be associated with other illnesses. Daszak suggests testing key species for antibodies against the virus. This is a viable strategy as antibody test kits are relatively cheap and easy to use according to an immunologist at the Trinity College of Dublin in Ireland.