BHUBANESWAR: The first ever study by research labs in Odisha on SARSCoV2 genomes sequenced here has found prominent and distinct presence of three clades of the virus responsible for spread of Covid-19 in certain pockets of the State. The genome analysis carried out by Institute of Life Sciences (ILS) and Regional Medical Research Centre (RMRC) observed B4, A2 and A2a clades in the genomes extracted from samples mostly collected from Ganjam and Khurda districts.
“We initially performed whole-genome sequencing for 45 genomes and their phylogenetic clustering besides substitution analysis. As per the phylogenetic analysis, ten genomes fell into B4 clade and the rest, to A2 and A2a clades. B4 clade is mostly found in genomes sequenced in Gujarat and is the most evolved one,” said a scientist involved in the project. Of the basic 10 clades of 2019-nCoV genomes - A1a, A2, A2a, A3, A6, A7, B, B1, B2 and B4, coronavirus isolates largely cluster into six clades - A1a, A2, A2a, A3, B and B4 - in India.
“We found full coverage of genomes in 36 samples and eight to 10 per cent less coverage in nine other samples. The samples were anonymised by removing identification details of patients. The evolved B4 clade was found in samples from Ganjam which is why symptomatic cases are high in the district. The rest samples were of Tablighi Jamaat returnees besides one of foreign returned,” the scientist said. The initial genomes from Gujarat fell into the B clade and those were from individuals, who had travelled from Abu Dhabi and Dubai. B4 clade is a sub-type of the super-clade B.
Both the labs are conducting sequencing of 180 more genomes collected from samples of affected persons of different districts witnessing influx of migrants from West Bengal, Gujarat and Maharashtra where fatality rate is higher. So, why are majority of the cases in Odisha asymptomatic? “It is more of immune-response of people than the virus clades. We have started conducting a study on the immune profile of people. We will profile the antibody and cells of patients. Hopefully, the f indings wi l l be out soon,” he added.
The research teams - led by Dr Sunil Raghav of ILS, an autonomous institution under Department of Biotechnology, and Dr Jyotirmayee Turuk of RMRC - carried out Covid-19 genome sequencing of viral strains obtained from Odisha cases. The sequence information has been submitted to the Global Initiative on Sharing All Influenza Data (GISAID) database. “The data will be of great relevance in understanding migration of viral strain from point of origin. It will elucidate the pathotypes and provide information on diversity and virulence of the strains,” said Dr Raghav.