Hyderabad: The first strain of the SARS Cov-2 virus — the so-called L strain — which initially caused Covid-19 is slowly disappearing according to 48,653 genomes that were studied by researchers and published in the journal Frontiers of Microbiology.
The L strain, which was widespread in Wuhan, has mutated during its journey to different continents and five different strains have been produced.
The L strain from Wuhan emerged in December 2019 and the first mutation was the S strain that appeared in the beginning of 2020. After that, there were strains G and V which have been produced in mid-January 2020 as they spread to different parts.
The G strain is most widespread till date and it has mutated to GR and GH strains in February 2020. In India, earlier there was L strain and then G and GH strains have been dominant. According to the Centre for Cellular and Molecular Biology (CCMB), there has also been Clade A 3i which has been found to be very virulent in India. These were found in Maharashtra, Tamil Nadu and Delhi and also parts of Telangana.
There are different samples which are being collected from states and the genomic studies are being carried out.
The genomic study of the virus is important for development of drugs for the disease and also checking use of old molecules on the virus. Presently, CCMB has got more than 20 different molecules for testing on whether it will work on the virus. The scientists are looking at the different strains and the impact of medicines on them to understand how treatment can be further improved.
Meanwhile the biggest worry was whether like the influenza virus, the coronavirus will be variable but it has been found that, despite mutations, variability will be limited. This means that despite the different strains due to mutations, the virus structure has remained the same.
A scientist at CCMB explained, “Less variability means that even if there is a mutation the vaccine will work for all the strains of coronavirus. This is positive news. The disappearing strain L also shows that due to constant mutations there are chances that other strains will slowly disappear and there may be new ones or they may not be. Or it could also mean that there is immunity developing for some strains.”