Washington (AFP)
The new coronavirus began spreading in New York in February, before large-scale drug testing began, and the strain was apparently from Europe, a team of American geneticists announced on Wednesday.
Tracing the chain of transmission of the virus responsible for the Covid-19 pandemic will be useful in shaping the response of governments in future epidemics, the researchers say.
"It is interesting that, at this stage, the majority (of the cases) seems to have arrived from Europe, which is undoubtedly explained by the fact that the flights were stopped from China", told AFP Adriana Heguy, geneticist at New York University and responsible for the study.
Scientists have sequenced the viruses from 75 samples taken from the nasal cavities of patients at three New York hospitals.
All viruses mutate constantly by replicating, and each cycle causes small errors, which allow researchers to reconstruct a kind of family tree to reconstruct the route of a virus.
The first patient analyzed had not traveled abroad and had therefore caught the virus locally.
"By observing the specific changes in his virus, we were able to say, with high probability, that he came from England," said the researcher.
The interest of these genetic investigations is also clinical: perhaps doctors will end up realizing that certain strains cause more severe forms of the disease than others, requiring different treatments.
The New York team wants to amplify its sequencing program and increase to 200 samples per week, in order to build a library of thousands of genomes. Multiple research centers around the world carry out similar analyzes and share their data in common databases.
© 2020 AFP