A study published in the American scientific journal Cellthis Thursday the 19th, revealed that raccoon dogs and civets are among the species most likely to have served as hosts for SARS-CoV-2, the virus responsible for the Covid-19 pandemic.
The research was led by French scientist Florence Débarre, from the National Center for Scientific Research, and showed which species were present at the end of 2019 in the Wuhan marketin China, the epicenter of the pandemic, and which would have transmitted the virus to humans.
According to a statement released by the French research center, after carrying out genetic sequencing of samples taken from market stalls, scientists detected the simultaneous presence of genetic material from the SARS-CoV-2 virus and some wild animals at the site.
The samples were collected after the site closed, on January 1, 2020, a few months before the virus spread throughout the world.
Among the animals identified are raccoon dogs and civets, which were already involved in the spread of the SARS virus in 2002. Both species are considered by scientists to “facilitate” the passage of the virus to humans.
The technique used to sequence the samples, according to the statement, is known as metatranscriptomics. The method is a sophisticated biotechnology tool, which allows the extraction of RNA and the analysis of the expression of genes from microbes, for example.
This technique allowed researchers to identify all the genetic material of the organisms present in each sample. These include viruses such as SARS-CoV-2, bacteria, plants, animals or humans.
“The analysis of sequencing data made it possible to characterize the genetic composition of animals present on the market and determine their probable geographic origin”, says the CNRS statement.
In parallel, scientists studied the viral genomes of the first patients who had Covid-19 to track the possible evolution of the virus.
According to the study, scientists demonstrated that the genetic diversity of the virus present on the market was close to the genetic diversity of the first human cases of the pandemic. The result obtained by the researchers corroborates the thesis that the epidemic began in the Chinese market at the end of 2019, confirming other studies that reached the same conclusion.
The research also revealed the presence of other zoonotic viruses in the Wuhan market. For researchers, this reveals the risk of new pandemics linked to the sale of live wild animals in cities with high demographic density. “Identifying the human activities most likely to trigger new pandemics is indeed crucial to anticipate and prevent health crises,” concludes the French institute in its statement.
New variant of the virus spreads in Europe
First detected in Berlin in early June, the XEC variant is expected to become the next dominant strain of Covid-19.
It is currently spreading “rapidly” across Europe, South America and Asia, and already accounts for 10% of cases in August in Slovenia.
XEC is a subvariant of Ômicron, which emerged in 2021 and became dominant. The first data shows that it is a little more contagious.
The XEC variant of Covid-19 appears to have similar symptoms to the previous ones, such as fever, sore throat, cough and body aches, in addition to loss of smell and appetite.
The updated vaccines do not yet include XEC, but as they protect against Ômicron, they remain effective and prevent serious forms of the disease.
In France, the booster dose is recommended for people over 65 years of age, who live or work in contact with the elderly, and patients with comorbidities, as well as healthcare professionals. The reinforcement campaign in the country should begin on October 15th.
