The appearance of the Wuhan coronavirus (2019-nCoV) in December 2019 has not only generated social alarm due to its spread around the world and its potential mortality. It also poses a new challenge for scientists as it is a completely new type of coronavirus, and details about its epidemiology, its genetic sequence and its ways of spread are still unknown.
Coronaviruses are the types of viruses that cause common colds. But this new type of coronavirus requires a previously unknown level of understanding; to begin with, about its origin.
The WHO hypothesis is that an animal-human contagion occurred in a live market in the city of Wuhan. Now, this hypothesis has been strongly reinforced by a recent study in the Journal of Medical Virology.
It explains how scientists have carried out an analysis comparing the genetic sequences of 2019-nCoV with all the rest of known coronaviruses.
The findings revealed that the new virus is most closely related to two bat SARS-like coronavirus samples from China. The authors also discovered that the viral RNA coding sequence for the spike protein 2019-nCoV, (which recognizes the receptor in a host cell), indicates that the virus may have mutated before infecting people.
Although these conclusions are confusing, due to the results of a later analysis:
After a detailed bioinformatic analysis of the 2019-nCoV sequence, it was concluded that this coronavirus could actually come from two common snakes in southeast China , the pluriband krait ( Bungarus multicinctus ) and the Chinese cobra Naja. atra, both traded in the Wujan food market where the spread is suspected to have started.
But this last conclusion seems out of the question for now, given that all we know about coronaviruses and pneumonia-like diseases like SARS is that these types of viruses are only transmitted between mammals.
Analysis of the Wuhan coronavirus genome reveals little genetic diversity, and it is not yet possible to determine whether the most recent common ancestor resided in a human or an animal.
Since snakes often hunt bats in the wild, one possibility is that the coronavirus has been transmitted from the bat to the snake, with the snake being the epidemiological reservoir (which carries the virus) and from the snake, to humans. But how the virus could adapt to both cold-blooded and warm-blooded hosts remains a mystery.
Therefore, it is still too early to determine the epidemiology of the virus, and scientists are still using mere hypotheses.
The Wuhan coronavirus accounts for about 200 deaths globally, and there are more than 10,000 infected worldwide. The most vulnerable people are children, the elderly, pregnant women, or people with depressed immune systems or respiratory conditions.
Identifying the origin of this virus is a fundamental challenge for scientists, in order to develop a possible vaccine.
