Reason behind Monkeypox spread - sex at 2 rave parties: Experts

Other scientists have pointed out that it will be difficult to disentangle whether it is sex itself or the close contact related to sex that has driven the recent spread of monkeypox across Europe.

A leading adviser to the World Health Organization described the unprecedented outbreak of the rare disease monkeypox in developed countries as a random event that might be explained by risky sexual behaviour at two recent mass events in Europe. In an interview with The Associated Press, Dr David Heymann, who formerly headed WHO's emergencies department, said the leading theory to explain the spread of the disease was sexual transmission among gay and bisexual men at two raves held in Spain and Belgium. Monkeypox has not previously triggered widespread outbreaks beyond Africa, where it is endemic in animals.

"We know monkeypox can spread when there is close contact with the lesions of someone who is infected, and it looks like sexual contact has now amplified that transmission," said Heymann.

That marks a significant departure from the disease's typical pattern of spread in central and western Africa, where people are mainly infected by animals like wild rodents and primates and outbreaks have not spilled across borders.

To date, WHO has recorded more than 90 cases of monkeypox in a dozen countries including Britain, Spain, Israel, France, Switzerland, the US and Australia. Madrid's senior health official said on Monday that the Spanish capital has recorded 30 confirmed cases so far. Enrique Ruiz Escudero said authorities are investigating possible links between a recent Gay Pride event in the Canary Islands, which drew some 80,000 people, and cases at a Madrid sauna.

Heymann chaired an urgent meeting of WHO's advisory group on infectious disease threats on Friday to assess the ongoing epidemic and said there was no evidence to suggest that monkeypox might have mutated into a more infectious form.