For the first time, scientists in India have carried out an in-depth genetic analysis of a newer Mpox variant, linking recent cases in Kerala to international travel and confirming signs of continued human-to-human transmission.
Focus on Emerging Mpox Clade Ib
As reported by TOI, the study focused on Mpox Clade Ib, a recently emerged variant that has driven outbreaks in parts of Africa and has now appeared in several countries beyond the continent. Unlike earlier Mpox strains, which were largely associated with animal-to-human transmission, Clade Ib shows clearer evidence of sustained spread between people, raising global public health concerns and triggering enhanced surveillance.
ICMR-NIV Leads Nationwide Research Effort
Researchers from the Indian Council of Medical Research–National Institute of Virology (ICMR-NIV), Pune, along with scientists from multiple institutions across India—primarily Viral Research and Diagnostic Laboratories (VRDLs)—led the study. The team analysed 10 laboratory-confirmed Mpox Clade Ib cases detected in Kerala between September 2024 and March 2025.
Evidence of Active Viral Evolution
Published in the journal Virology, the findings point to active viral evolution with important implications for disease surveillance and preparedness.
“The study confirmed that the Mpox virus is mutating, with a distinctive pattern that signals sustained human-to-human transmission,” a researcher involved in the study said.
Notably, scientists observed that this mutation pattern was stronger in Clade Ib than in older Mpox variants, suggesting that the virus continues to adapt as it circulates among people.
Shared Mutations Across Regions
In addition, the genetic sequences showed mutations in several genes previously identified as hotspots in Clade Ib strains from the Democratic Republic of Congo. This finding points to evolutionary convergence across different geographic regions.
Moreover, researchers detected a new mutation in six of the ten cases, which they are now studying further to understand its significance.
Travel-Linked Spread, Not a Single Entry Event
Beyond genetics, the team examined clinical symptoms, viral load, immune responses, and complete viral genomes. Together, the data suggested that the virus did not enter India through a single case. Instead, it likely arrived as part of a broader regional spread linked to international travel.
Epidemiological analysis revealed that nine of the ten patients had recently travelled abroad. In one case, researchers documented local transmission, where a patient was infected through close contact with a family member who had an international travel history.
Early Detection Before Global Reporting
Importantly, the study noted that travel-linked Clade Ib cases appeared in India as early as 2024, well before the World Health Organization formally reported the first global Clade Ib case in February 2025. This timing raises the possibility of undetected or underreported transmission at international travel hubs, the authors observed.
Collaborative Scientific Effort
The research team included scientists Dr Pragya Yadav, Dr Rima R. Sahay, and Dr Anita M. Shete, along with several VRDL researchers across the country. Together, their work provides critical insights into the evolution, spread, and public health risks of Mpox Clade Ib and underscores the need for continued genomic surveillance and global cooperation.