A leading adviser to the World Health Organization has described the unprecedented outbreak of monkeypox in developed countries as “a random event” that might be explained by risky sexual behavior at two recent mass events in Europe.
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.
Heymann said 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.
Heymann, who is also a professor of infectious diseases at the London School of Hygiene and Tropical Medicine, said the monkeypox outbreak was likely a random event that might be traceable to a single infection.
Also watch: Explained: what is monkeypox, its symptoms and chances of human transmission
To date, WHO has recorded more than 90 cases of monkeypox in a dozen countries including Britain, Spain, Israel, France, Switzerland, the U.S. and Australia.
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 spread across borders.