The evolving landscape of Mpox: Clinical and genomic insights into Clade Ib emergence in India.

BACKGROUND

The re-emergence of Mpox virus (MPXV) Clade Ib has posed a global public health threat, prompting a WHO Public Health Emergency of International Concern in May 2022 and August 2024. This study aims to outline the clinical, viral, and genomic characterization of MPXV Clade Ib cases found in Kerala, India.

METHODS

We profiled ten laboratory-confirmed MPXV cases from September 2024 to March 2025. Mpox DNA was screened using real-time PCR, and anti-MPXV IgM and IgG antibodies were detected by ELISA. Full-length genomic sequencing and phylogenetic analysis were performed on the clinical samples.

RESULTS

The median age of the cases was 34 years, with a male predominance (80 %). Most (90 %) had a recent history of international travel, primarily to the United Arab Emirates (UAE), with one documented case of local transmission. All cases presented with vesiculo-pustular lesions, fever, and lymphadenopathy, and all recovered without complications. Mpox DNA was cleared between 20 and 28 days, though prolonged shedding was observed in some. Phylogenetic analysis clustered the Indian sequences with those from Oman, Pakistan and Thailand, suggesting a shared regional lineage. The presence of APOBEC3-mediated mutational signatures was high, indicative of sustained human-to-human transmission.

CONCLUSION

This research presents the first in-depth analysis of the clinical and genomic characteristics of MPXV Clade Ib identified in India. The findings highlight the critical role of international travel in virus introduction and indicate local transmission following introduction, with regional linkage inferred from epidemiological evidence. These findings suggest ongoing viral evolution and the need for enhanced surveillance.