Genetic analysis links Kerala's 2024 mpox outbreak to international travel

Cases from Kerala’s 2024 mpox outbreak have been linked primarily to international travel from the United Arab Emirates, according to a genetic analysis.

Mpox, previously known as monkeypox, is a viral illness caused by the monkeypox virus. Common symptoms include a skin rash or lesions in the mucous that can last two to four weeks, along with fever, headache and muscle or back pain, low energy and swollen lymph nodes.

Researchers, including those from the Indian Council of Medical Research-National Institute of Virology in Pune, analysed 10 lab-confirmed cases of Mpox virus (MPXV) Clade Ib strain reported from September 2024 to March 2025.

Findings of the first in-depth analysis of clinical and genomic characteristics of the Clade Ib strain, published in the journal Virology, showed seven of the 10 individuals had a history of travel to the United Arab Emirates (UAE).

“From Kerala state, India, total of ten cases of mpox Clade Ib were identified from September 2024 to March 2025... Notably, 70 per cent of the individuals had a history of travel to the United Arab Emirates (UAE), while one case had travelled from Oman, and another was a contact case,” the authors wrote.

The first case of MPXV Clade Ib was identified in the Democratic Republic of Congo in September 2023. Since its emergence, the virus has spread to other countries in the African continent, including Uganda, Rwanda, Kenya, and Burundi.

On August 14, 2024, the World Health Organization declared the mpox outbreak a public health emergency of international concern due to the Clade Ib strain’s rapid spread and disease severity.

Outside Africa, the Clade Ib strain was first detected in Sweden, with subsequent detections in the UK, India, US and China.

As of early 2025, more than 22,000 confirmed or suspected cases of Mpox caused by Clade Ib have been reported globally, with over 60 deaths attributed to this clade, most of them occurring in the Democratic Republic of Congo, the researchers said.

They added that the fatality rate for the Clade Ib strain is about three per cent higher than that for Clade IIb - the strain predominant during the 2022 outbreak.

“Clade IIb is notable for its efficient human-to-human transmission via both sexual and non-sexual contact with infected individuals,” the authors said.

They added that the the Clade IIb sub-lineage A.2 predominantly drove the 2022 multi-country outbreak, which accounted for over 102,000 cases globally and prompted the WHO declare a public health emergency of international concern in July 2022.