Dr David Heymann, who formerly headed the WHO’s emergencies department, told the Associated Press that the leading theory out of many put forward to explain the spread of the disease was sexual transmission at raves in Europe.
Monkeypox has not previously triggered widespread outbreaks beyond Africa, where it is endemic in animals.
The WHO has recorded more than 90 cases of monkeypox in a dozen countries including Canada, Spain, Israel, France, Switzerland, the US and Australia. On Monday, Denmark announced its first case, Portugal revised its total up to 37, Italy reported one further infection and Britain added 37 more cases.
Germany has four confirmed cases linked to exposure at “party events… where sexual activity took place” in Spain’s Canary Islands and in Berlin, according to a government report obtained by the AP.
The UK Health Security Agency (UKHSA) said a total of 70 cases have been confirmed in England since May 7.
Scotland confirmed its first case on Monday, bringing the UK total to 71.
“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 Dr 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.
Dr Heymann, who is also a professor of infectious diseases at the London School of Hygiene and Tropical Medicine, said: “It’s very possible there was somebody who got infected, developed lesions on the genitals, hands or somewhere else, and then spread it to others when there was sexual or close physical contact.
“And then there were these international events that seeded the outbreak around the world, into the US and other European countries. This is not Covid. We need to slow it down, but it does not spread in the air and we have vaccines to protect against it.”
Symptoms of monkeypox in humans
A rash usually appears 1 to 5 days after the first symptoms. The rash often begins on the face, then spreads to other parts of the body.
Full list of symptoms:
- a high temperature
- a headache
- muscle aches
- swollen glands
- shivering (chills)
The symptoms usually clear up in 2 to 4 weeks.