Strain detected in India not linked to Europe outbreak
Genome sequencing reports from two monkeypox patients in Kerala suggests they were infected with the A.2 strain of the virus, different from the one causing the monkeypox outbreaks in Europe, an analysis by scientists at CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB).
This A.2 strain, which has largely been found in the US and Thailand, has not been linked to major cluster or super spreader events, unlike the B.1, which has been found in large parts of Europe. To be sure, there is no evidence yet that suggests either of the strain may be more infectious or virulent.
Vinod Scaria, genome sequencing scientist at IGIB, said that genome sequencing data from two monkeypox patients from Kerala belong to the A.2 version of the monkeypox virus, in contrast to majority of the genomes across the world which belongs to B.1 lineage. Of the four confirmed cases in India, these are the only two samples that have been sequenced for now, officials confirmed.
“Genome sequences have been deposited for two samples along with two re-sequenced genomes from isolates of one of the sample. Both the isolates were from early cases reported from Kerala and both cases have a travel history,” Scaria said. Scaria said that around the world, there are only a few cases that belong to the A.2 strain and these cases, including the ones from India, seem to all have travel links to Middle East or West Africa. “The earliest sample in the cluster from US is indeed from 2021 suggesting the virus has been in circulation for quite some time, and earlier than the European events,” he added.
The samples from the monkeypox patients were collected by the National Institute of Virology in Pune, and the genetic sequences of the monkeypox virus has been uploaded on a public database for researchers, GISAID—a global initiative for real time communication for disease prevention.
Dr Priya Abraham, director, ICMR-National Institute of Virology, Pune, explained that all viruses over time undergo slow evolution and as they evolve, they form into different evolutionary branches. This is no cause of panic or alarm, she said. “There are two outbreaks of monkeypox that are going on simultaneously, but it is too early to provide details about A.2 and B.1 clade and say for sure if one is more transmissible than the other. The sequence that we had submitted from Kerala is falling in the A.2 clade. Out of thousands of infections of monkeypox around the world, five deaths have been reported, and there is no scientific evidence to connect these deaths to any particular variant. However, studying samples and inferring the behaviour of mutations will take some time,” said Dr Pragya Yadav, a senior scientist at NIV Pune.
Dr Ekta Gupta, professor of clinical virology at the Institute of Liver and Biliary Sciences (ILBS), said that there is no literature to suggest the B.1 strain is more transmissible than A.2 but based on the outbreak number of case in Europe, which primarily had B.1 strain, it is being speculated that this virus could be more transmissible.