Britain has detected its first case of new mpox variant clade Ib, the country's health security agency (UKHSA) said Wednesday, adding that the risk to the population remained low.

The clade Ib variant is a new form of the virus that was declared a global health emergency by the World Health Organization (WHO) in August after an outbreak in the Democratic Republic of Congo spread to neighboring countries in Africa.

The case, in a patient who had recently traveled to affected countries in Africa, was detected in London and the individual has been transferred to a specialist hospital, the UKHSA said.

Close contacts of the case are being followed up by UKHSA and partner organizations, the UKHSA added.

There have been cases of mpox clade Ib reported in Burundi, Rwanda, Uganda, Kenya, Sweden, India and Germany, as well as Congo. 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.

The United Kingdom authorities said they would not provide any more details about the patient, but added that the person's contacts were being followed up and would be offered testing and vaccination as needed, as well as further care if they test positive or have symptoms.

According to the latest WHO figures, there have been more than 44,000 confirmed and suspected cases of mpox in Africa this year, and more than 1,000 deaths, largely in Congo.