LONDON (Reuters) -Britain has detected two more cases of the new mpox variant clade Ib in household contacts of the first case, the country’s health security agency (UKHSA) said on Monday, bringing the total number of confirmed cases to three.

The government agency that added the risk to the population remained low. The clade Ib variant is a new form of the virus that is linked to a global health emergency declared by the World Health Organization in August.

“Mpox is very infectious in households with close contact and so it is not unexpected to see further cases within the same household,” UKHSA said.

UKHSA said last week that the first case, in a patient who had recently travelled to affected countries in Africa, was detected in London and the individual has been transferred to a specialist hospital.

The two new patients are also under specialist care in the city, UKHSA said, adding that healthcare professionals are equipped and prepared to respond to any further confirmed cases.

Nineteen African countries have seen more than 48,000 suspected mpox cases, including 1,048 deaths so far this year, according to the Africa Centres for Disease Control and Prevention (Africa CDC), with cases in the continent surging by 500% from last year.

Mpox clade Ib has also been reported in Germany, Sweden, India and Thailand. It is a different form of the virus from clade II, which spread globally in 2022, largely among men who have sex with men.

Mpox is a viral infection that typically causes flu-like symptoms and pus-filled lesions, and while usually mild it can kill. Clade Ib is thought to cause more severe disease than clade II.

Both forms can be transmitted through close physical contact, including sexual contact.

(Reporting by Muvija M and Urvi DugarEditing by Chris Reese, Chizu Nomiyama and Marguerita Choy)