LONDON — British health officials say there have now been 1,735 confirmed cases of monkeypox and that three-quarters of those cases are in London, according to data released on Tuesday.

In a review of the outbreak published last week, Britain’s Health Security Agency said there were “no signs of a decline” in the monkeypox epidemic.

British scientists estimate the outbreak is doubling in size about every two weeks and said it’s likely cases are being undercounted.

They said that in nearly 80% of cases, there is no information about whether or not the person had contact with a confirmed case, meaning the virus is spreading undetected.

Scientists have noted that people with unusual symptoms, including only a single lesion, have been detected in the outbreak and say there have also been reports elsewhere of people with no symptoms carrying monkeypox.

About 10% of infected people in the U.K. have been hospitalized, but there have been no deaths reported.

Last month, the World Health Organization declined to declare monkeypox a global health emergency, but said it would revisit its decision soon.

People with monkeypox often experience symptoms like fever, body aches and a rash; most recover within weeks without needing medical care.

In central and west Africa, where the disease has been endemic for decades, the disease mostly affects people who come into contact with infected wild animals, like rodents or primates.

There have been about 1,500 reported cases of monkeypox, including 70 deaths, in Congo, Cameroon and the Central African Republic.

According to the U.S. Centers for Disease Control and Prevention, there are more than 9.600 cases of monkeypox worldwide in nearly 60 countries, most of which had not previously reported the disease. — Agencies