Study suggests COVID-19 may have originated as early as September

A Cambridge study, which is yet to be peer-reviewed, has used genetic data to suggest that COVID-19 may have originated in September - earlier than previously thought. Further, using genetic mapping, the researchers believe that the virus originated not in Wuhan, but from the southern part of China.[caption id="attachment_8237661" align="alignleft" width="380"] Representational image. Image by HenkieTenk from Pixabay.[/caption]The same team of researchers had previously published findings in PNAS (Proceedings of the National Academy of Sciences) that suggested that the virus strain seen in Australia and the US genetically resembled the variant seen in Southeast Asia, whereas the strains seen in Europe appeared to be descendants of the ones seen in Southeast Asia.

What were the findings of the study?

By studying 1,001 complete SARS-CoV-2 genetic sequences from across the world the scientists approximated that the virus may have initially started infecting people in the range of September 13 and December 7.Using phylogenetic network analysis (a method used to chart the movement and mutations of organisms across the world), the scientists examined the mutations to determine how far the virus went back before it became efficient enough for human-to-human transmission and strong enough to cause disease.While it hasn’t been confirmed yet, it is believed that the virus originated in bats. Sequencing studies have shown a 96% genetic relation with bat droppings from Yunnan in Southwestern China. Among the assumptions made by the researchers was that the virus mutates once a month, meaning that the virus could have been percolating in humans before it mutated into a disease-causing form that led to the initial outbreak. They came up with the time period of the initial outbreak by studying the mutations of the virus over a period of time.

What can we take from the study?

The study has limitations. Phylogenetic studies are influenced by sample size and mutation number; the sample size is small, and since the virus is novel, there is not a deep understanding of how it mutates. Viruses also mutate randomly which makes it hard to make projections. The findings should, therefore, be approached with caution.However, the genome sequences could shed light on how the virus ‘hopped’ from animals to humans, and if the geographical differences in strains are meaningful. This may help plan future responses and further our understanding of zoonotic diseases.For more information, read our article on Timeline: COVID-19.Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.