Two new cases of the M-pox variant clade 1b detected in the U.K. are the first locally transmitted cases in Europe and the first outside Africa, the World Health Organization said on Tuesday.

The U.K. Health Security Agency (UKHSA) confirmed late Monday that the two new cases were household contacts of Britain's first case identified last week, bringing the country's total confirmed cases to three.

The WHO warned that European states should be prepared for "rapid action" to contain the latest M-pox variant, which spreads through close physical contact, including sexual relations and sharing closed spaces.

The two cases are also the first to be locally transmitted outside Africa since August 2024, when the WHO declared the outbreak of the new variant an international public health emergency - its highest level of alarm.

The original case was detected after the person traveled to several African countries on holiday and returned to the U.K. on Oct. 21.

The patient developed flu-like symptoms more than 24 hours later and, on Oct. 24, started to develop a rash that worsened in the following days.

M-pox, a viral disease related to smallpox, has two types, clade 1 and clade 2. Symptoms include fever, a skin rash or pus-filled blisters, swollen lymph nodes and body aches.

The WHO first declared an international public health emergency in 2022 over the spread of clade 2. That outbreak mostly affected gay and bisexual men in Europe and the United States.

Vaccination and awareness drives in many countries helped stem the number of worldwide cases and the WHO lifted the emergency in May 2023 after reporting 140 deaths out of around 87,400 cases.

In 2024, a two-pronged epidemic of clade 1 and clade 1b, a new strain that affects children, has spread widely in the Democratic Republic of Congo.

The new strain has also been recorded in neighboring Burundi, Kenya, Rwanda and Uganda, with imported cases in Sweden, India, Thailand, Germany and the U.K.

VOA/SD