Thailand has confirmed Asia’s first known case of a new, deadlier strain of mpox in a patient who had travelled to the country from Africa.

The department of disease control said laboratory tests on the 66-year-old had confirmed he was infected with the mpox Clade 1b variant.

“Thailand’s Department of Disease Control wishes to confirm the lab test result which shows mpox Clade 1b in a European patient,” the department said in a statement, adding that the World Health Organization (WHO) would be informed of the development.

The World Health Organization has declared a global public health emergency over the new variant, urging manufacturers to ramp up production of vaccines.

The patient landed in Bangkok on 14 August and was sent to hospital with mpox symptoms.

“We have monitored 43 people who have been in close contact with the patient and so far they have shown no symptoms, but we must continue monitoring for a total of 21 days,” said the department.

Anyone travelling to Thailand from 42 “risk countries” must register and undergo testing on arrival, the department added.

Mpox cases and deaths are surging in Africa, where outbreaks have been reported in the Democratic Republic of Congo, Burundi, Kenya, Rwanda and Uganda since July.

Sweden also confirmed its first case of the more contagious variant earlier in August and Argentina has quarantined a cargo ship over a suspected case of mpox on board, although it is not known if it is the new faster spreading variant.

The disease is caused by a virus transmitted by infected animals but passed from human to human through close physical contact. It causes fever, muscular aches and large boil-like skin lesions.

While mpox has been known for decades, a new deadlier and more transmissible strain – known as Clade 1b – has driven the recent surge in cases.

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

But Thongchai Keeratihattayakorn, head of the Thai Department of Disease Control, said that mpox was much less likely to spread rapidly than Covid-19 because of the close contact needed to catch it.

With Agence France-Presse and Reuters