Where Did the COVID-19 Virus Come From?

Dawn O'Shea

April 14, 2020

Researchers from the UK and Germany have reconstructed the early 'evolutionary paths' of COVID-19 as it spread from Wuhan out to Europe and North America.

The researchers analysing 160 complete virus genomes sampled from patients across the world between 24th December 2019 and 4th March 2020.

They found that the closest type of COVID-19 to the one discovered in bats (type A) - the original human virus genome - was present in Wuhan, but surprisingly was not the city’s predominant virus type.

Mutated versions of A were seen in Americans reported to have lived in Wuhan, and a large number of A-type viruses were found in patients from the US and Australia.

Wuhan’s major virus type (B) was prevalent in patients from across East Asia. However, the variant did not travel much beyond the region without further mutations, implying a founder event in Wuhan or resistance against this type of COVID-19 outside East Asia, say the researchers.

The C variant is the major European type, found in early patients from France, Italy, Sweden and England. It is absent from the study’s Chinese mainland sample, but seen in Singapore, Hong Kong and South Korea.

The new analysis also suggests that one of the earliest introductions of the virus into Italy came via the first documented German infection on January 27th, and that another early Italian infection route was related to a Singapore cluster.

The findings are published in the journal Proceedings of the National Academy of Sciences (PNAS).

Forster P, Forster L, Renfrew C, Forster M. Phylogenetic network analysis of SARS-CoV-2 genomes. Proc. Natl. Acad. Sci. U.S.A. 2020 Apr 08 [Epub ahead of print]. doi: 10.1073/pnas.2004999117. PMID: 32269081. View abstract. View full text (free).

Adapted from Univadis from Medscape.


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