First case of new mpox strain confirmed in Asia: Why is it dangerous?

Thailand confirmed the first case of the new mpox strain, which means that the Clade 1b strain has entered Asia. Bangladesh and Pakistan have report mpox cases as well, but those are of the Clade 2 strain, the less severe variant of mpox.

Mpox, now a global health emergency disease declared by the World Health Organisation (WHO), has two main strains circulating worldwide.

There are two strains of mpox (formerly known as monkeypox): clade 1b and clade 2.

The risk of severe disease and death depends on the strain of the virus as well as pre-existing health conditions and secondary infections.

“While strain clade 2 is milder and was responsible for the 2022 outbreak, the worry in 2024 is that the slightly more severe strain called clade 1, which is usually restricted to a few African countries has been causing cases in Sweden, Philippines and Pakistan,” Dr Vikram Vora, Medical Director of International SOS, told IndiaToday.in.

According to Dr Koulsoum Houssein, Consultant Physician in Medicine, Holy Family Hospital, clade 2 is “less severe and self-limiting,” causing severe infections and death mainly in immunocompromised and advanced HIV persons.

“In contrast, the current strain which is attributed to clade 1, affects in majority (more than 50%) children younger than 5 years and causes a higher mortality,” Dr Houssein said.

There are also currently clusters of transmission linked to heterosexual intimate or sexual contact, attributed to a new lineage clade 1b. Heterosexual transmission was not common in the 2022 epidemic of clade 2, the expert noted.

“Clade 1b presents as a disseminated whole body rash or long lasting genital lesions thus, contributing to even spread through direct skin contact or materials contaminated with the virus. Sometimes even through respiratory droplets,” Dr Houssein said.

Clade 1b, which spread rapidly in the Democratic Republic of Congo which triggered WHO’s declaration, also has a higher fatality risk of 5% in adults and 10% in children which is much higher as compared to clade 2 (less than 1%).

Human-to-human transmission of mpox occurs due to close contact, sexual contact or direct contact with the body fluids of an infected person, contact with rashes or pustules of an infected case, prolonged face-to-face contact with a sick person, and after touching virus-contaminated objects, such as shared bedding or clothing.

The clade 1b, which is being dubbed as a new strain, is not a new variant. It was earlier known as the Central African (Congo Basin) strain.

According to the WHO, clade 1b causes death in about 3.6% of cases, with children more at risk.

Following mpox becoming a global health issue, India has directed hospitals, airports and border controls to isolate, manage and treat mpox patients. While the country is on high alert, no mpox case has been reported so far.