Monkeypox, a rare viral condition found in remote parts of Central and West Africa, has been confirmed in 80 cases across 12 countries: the United States, Canada and Australia, and nine European states including Britain.

According to the BBC, the World Health Organization (WHO) says another 50 suspected cases are being investigated, warning that more cases are likely to be reported.

Britain’s National Health Service describes monkeypox as a rare viral infection which is usually mild and from which most people recover in a few weeks. The virus does not spread easily between people and the risk to the wider public is said to be very low.

While there is no specific vaccine for monkeypox, a smallpox jab offers 85% protection since the two viruses are quite similar.

The BBC says that, so far, public health agencies in Europe have confirmed cases in the UK, Spain, Portugal, Germany, Belgium, France, the Netherlands, Italy and Sweden.

The WHO said in a statement on Friday that the recent outbreaks ‘are atypical, as they are occurring in non-endemic countries’.

It is not yet clear why this unusual outbreak is happening now, the BBC says, noting that one possibility is that the virus has changed in some way, although currently there is little evidence to suggest this is a new variant.

WHO’s Europe regional director Hans Kluge warned that ‘as we enter the summer season… with mass gatherings, festivals and parties, I am concerned that transmission could accelerate’.

He added that all but one of the recent cases had no relevant travel history to areas where monkeypox was endemic.

The first case of the disease in the UK was reported on 7 May. The patient had recently travelled to Nigeria, and is said to have caught the virus there before travelling to England, the UK Health Security Agency said.

There are now 20 confirmed cases in the UK, Health Secretary Sajid Javid said on Friday.

Australia’s first case was detected in a man who fell ill after travelling to the UK, the Victorian Department of Health said. In North America, health authorities in the US state of Massachusetts confirmed that a man had been infected after recently travelling to Canada. He was in ‘good condition’ and ‘poses no risk to the public’, officials said.