In December 2019, 27 people out of the first 41 infected (66% of them) visited one of the markets of Wuhan, central China, but reports show that the first infected did not enter that market, while the estimate of the molecular history of the virus dates back to November 2019, which raises doubts About a possible relationship between disease and wildlife.

Chinese researchers studied the sequence of the virus's genome, a RNA molecule, consisting of about 30,000 nitrogenous bases, including 15 genes, including a gene called S, that encodes a protein on the surface of the viral sheath, and found it to be a hybrid virus from two pre-existing viruses. .

Comparative genomic analyzes showed that the virus belongs to the beta-corona virus group, and that it is very close to the SARS-Cove responsible for an acute pneumonia epidemic, which appeared in November 2002 in China's Guangdong Province, then spread to 29 countries in 2003, and was recorded at 8,098 One of these cases was 774 deaths, and it is known that the bats were the reservoir of this virus, and it is possible that the carnivorous palm-eating animal was an intermediate host between bats and the first human cases, according to the scientific website.

Since then, several beta-corona viruses have been discovered in bats and humans. For example, a newly described RTG13 virus, isolated from a bat caught in Yunnan Province of China, has been described as very similar to SARS Cove-2, with a match In the genome sequence it is 96%. These results indicate that bats, especially the Raynauloves species, form a reservoir for the SARS Cove and SARS Cove-2 viruses.

A previous report referred to the discovery of a virus closer to SARS Cove-2, on February 7, in the Malaysian squamous anteater, with genomic compatibility reported at 99%, which suggests that it is more likely to be a reservoir of the virus than bats.

Hybrid virus

These genomic comparisons indicate that the SARS Cove-2 virus is caused by recombination between two different viruses, one close to the RTG13, and the other closer to the isolated virus from the scaly anteater. In other words, it is a hybrid virus from two pre-existing viruses. For recombination to occur, the two separate viruses must simultaneously infect one organism. The question remains: In what object did this recombination take place, and under what circumstances?