New Delhi: Genetic sequencing of samples from the first two cases of monkeypox detected in India earlier this month show that the strain doing the rounds in the country is different from the ones associated with the ‘super-spreader’ events identified in Europe.
This suggests that a separate strain of the virus has been silently circulating among the global population since at least 2021.
Scientists from the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Pune, have uploaded the genetic sequences of the monkeypox virus on a public database for researchers, GISAID, a global science initiative. ThePrint has accessed the data.
At present, most of the over 20,000 monkeypox cases spread over 75 countries are believed to have happened through super-spreader events in Europe and a majority of these, identified in 2022, belong to the strain designated ‘B.1’.
However, a small cluster of cases from across the world appear to belong to a separate strain — ‘A.2’.
Speaking to ThePrint, genomic scientists from CSIR-IGIB (Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology) said that only a very few samples sequenced so far belong to the A.2 cluster — with the earliest genomes of these dating back to 2021.
In a twitter thread, Vinod Scaria, a leading genomic scientist with IGIB, said that the A.2 genomes are from the US and Thailand, and don’t appear to have originated from any events linked to Europe.
He went on to note that the two genomes identified in Kerala belong to this small distinct A.2 cluster. “We might be looking at a distinct cluster of human-human transmission and possibly unrecognised for years (sic),” he said.
?The curious case of Indian #Monkeypox Genomes
Wonderful effort by clinicians in @KeralaHealth who diagnosed the disease and researchers at @icmr_niv, we now have sequences of MPX isolates in @GISAID .
This short ?is on what the early genomes say.
Analysis @bani_jolly pic.twitter.com/xsQcOiQNHx
— Vinod Scaria (@vinodscaria) July 27, 2022
Scaria also pointed out that the few cases that belong to the A.2 strain — including the ones from India — seem to all have travel links to the Middle East or West Africa.
“The earliest sample in the cluster from USA is indeed from 2021 suggesting the virus has been in circulation for quite some time, and earlier than the European events,” he added.
Genetic data from the US last month had also revealed that there are at least two separate monkeypox outbreaks happening simultaneously.
The A.2 variant may have been silently spreading in the global population for a while and is only being detected now due to the European monkeypox outbreak.
(Edited by Zinnia Ray Chaudhuri)
Also read: Monkeypox: Origin, transmission and causes of concern