COVID-19 reminded everyone that sometimes viruses adapt so well that they can change their host species. This actually happens a lot in nature, but usually cross-species transmissions fail to establish in the newly- infected species.
Now a team of scientists led by the University of Glasgow looked at what separates failed and successful viral transmissions.
Scientists analysed hundreds of published infection experiments involving the transfer of rabies virus. Rabies is one of those diseases that crosses boundaries between species without a problem. All mammals can get infected with rabies, including humans, and in many cases it ends in death. Researchers found that when rabies originate in bats or are transferred from species with warmer body temperatures to those with a cooler body temperature, disease cannot spread, because the infected host dies too quickly.
The host has to be suitable for the virus. But just because it gets infected, doesn’t mean that a successful disease transmission can occur. The new host has to survive long enough to transfer these pathogens to someone else. Scientists say that cross-species transmission events are very difficult to observe in nature, which makes it difficult to predict how or when humans may be in danger of a new outbreak.
Dr Roman Biek, one of the authors of the study, said: “Our work shows how careful analysis of previous infection experiments can pinpoint small changes in the interaction between pathogen and host that may either help or hinder disease emergence, including emergence of new human infectious diseases.”
Scientists also stress that the currently available pool of data is large enough to study disease spread among different species. It is important to study this, because eventually it would allow predicting the spread of certain viruses. If some sort of monitoring method was developed, scientists could predict when a certain disease is likely to reach the human population.
It is believed that COVID-19 originated in bats. It is unclear how the SARS-CoV-2 virus reached people. Some say that coronaviruses are researched in labs in Wuhan and there might have been a problem with security. Others hypothesize that bat soup or bats sold in an exotic food market are to be blamed. However, research like this might help us understand the mechanism.
COVID-19 is not the last pandemic we have. It might not even be the last pandemic that you see in your lifetime. There are a lot of people in the world, we all live close together and viruses are mutating quickly. We either adapt or continue suffering through events like the COVID-19 pandemic, which may be continuing way into the summer of 2021 or even 2022.
Source: University of Glasgow