Pune: Scientists in India have, for the first time, conducted an in-depth genetic study of a newer Mpox variant detected in the country, linking recent Kerala cases to international travel and showing signs of continued human-to-human transmission.
The analysis focused on Mpox Clade Ib — a recently emerged variant of the virus that has been driving outbreaks in parts of Africa and has now been detected in several countries outside the continent.
Unlike older forms of Mpox that were mainly linked to animal-to-human transmission, Clade Ib showed clearer signs of sustained spread between people, prompting global health concerns and enhanced surveillance. The study, led by researchers from Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Pune, and several institutions from India, mainly Viral Research and Diagnostic Laboratories (VRDL), examined 10 laboratory-confirmed cases of Mpox Clade Ib identified from Sept 2024 to March 2025 in Kerala. The findings, published in the Journal Virology, indicated active viral evolution with implications for disease surveillance and public health preparedness. “The study confirmed that the Mpox virus is indeed mutating, as we found a distinctive mutational pattern that signals sustained human-to-human transmission,” a researcher involved in the study said. Scientists found that this mutation pattern was stronger in Clade Ib than in older forms of the virus, suggesting that it continues to adapt as it circulates among people. “The sequences also carried mutations in several genes that had earlier been identified as hotspots in Clade Ib strains from the Democratic Republic of Congo, pointing to evolutionary convergence across different regions,” a scientist involved in the study said. A new mutation was detected in 6 of 10 cases, which is being studied further. The researchers studied patients’ symptoms, how much virus they carried, their immune response, and the full genetic sequences of the virus.
Their findings suggested that the virus did not enter India through a single case, but arrived as part of a wider regional spread linked to international travel. Epidemiological analysis showed that 9 of the 10 patients had recently travelled abroad. Local transmission was noted in one case who was infected through close contact by a family member with a history of international travel. The study stated that Clade Ib cases linked to travel were detected in India as early as in 2024, before the World Health Organization formally reported the first Clade Ib case globally in Feb 2025. This raises the possibility of undetected or underreported transmission in international travel hubs, the authors said. The research team involved scientists Dr Pragya Yadav, Dr Rima R. Sahay, Dr Anita M. Shete, among others along with VRDL researchers.
