In a statement, Britain’s Health Security Agency said an investigation had begun into how the men became infected and whether they had any links to one another. Three of the men are in London and one in north-east England. All men identify as gay, bisexual, or men who have sex with men.
Last week Britain reported three previous cases of monkeypox, including two people living in the same household and the other having previously traveled to Nigeria, where the disease is endemic in animals.
“The evidence suggests that the monkeypox virus could be transmitted in the community through close contact,” said Dr. Susan Hopkins, the UK’s chief medical adviser. “We urge gay and bisexual men in particular to be alert for any unusual skin rash or lesion and to contact a sexual health service immediately.”
Monkeypox is a viral disease usually spread through touch or bite from infected wild animals such as rats or squirrels in West and Central Africa. The disease doesn’t usually spread easily between people, but UK health officials say it can if there’s been extremely close contact with an infected person.
Monkeypox is not known to be a sexually transmitted disease.
British authorities said that due to the recent spike in cases and uncertainty about how monkeypox is transmitted, they were working with hospitals and international partners to see if there had been a similar spike in cases elsewhere. Public health experts said doctors treating patients who develop rashes “without a clear alternative diagnosis” should seek specialist advice.
They said the risk to the general population was low and infected patients were receiving specialist care in London and Newcastle. Officials are tracking those who have had contact with the monkeypox cases, including airline passengers.
The early symptoms of monkeypox are fever, muscle aches, chills, and fatigue. In more severe cases, a rash may develop, often on the face and genitals, similar to those seen with chickenpox and smallpox. Most people recover from the disease within a few weeks.