European and American health officials have identified several cases of monkeypox recently, mostly in young men.
The cases reported in Europe and the United States are raising concern because the disease has rarely appeared outside of Africa.
International health officials say the risk to the general population is low. They are keeping watch for cases because, for the first time, the disease appears to be spreading among people who did not travel to Africa.
What is monkeypox?
Monkeypox is a virus from monkeys that was first identified in 1958. It spreads among wild animals and sometimes jumps to people.
Most human cases have been in central and west Africa, where the disease is endemic. The first known human infection was in 1970, in a 9-year-old boy in a distant part of Congo.
Symptoms and treatments
Monkeypox belongs to the same virus family as smallpox but causes milder symptoms.
Most patients only experience fever, body aches, chills and tiredness. People more seriously sick may develop a rash and cuts on their face and hands that can spread to other parts of the body.
The virus develops in a human body from about five days to three weeks after infection. Most people recover within about two to four weeks without needing to be hospitalized. Monkeypox can result in death for up to one in 10 people and is thought to be more severe in children.
People exposed to the virus are often given one of several smallpox vaccines, which have been shown to be effective against monkeypox. Anti-viral drugs are also being developed.
On Thursday, the European Center for Disease Prevention and Control said all suspected cases should be isolated and that high-risk contacts should be offered the smallpox vaccine.
How many cases are there?
The World Health Organization (WHO) estimates there are thousands of monkeypox infections in several African countries every year.
Most are in Congo, which reports about 6,000 cases yearly, and Nigeria, with about 3,000 cases a year. Experts say that many infected people are likely never identified as having the disease because of uneven reporting in the countries.
Isolated cases of monkeypox are sometimes reported outside of Africa, including in the U.S. and Britain. The cases are normally linked to travel to Africa or contact with animals from areas where the disease is more common.
In 2003, 47 people in the U.S. had confirmed or probable cases. They caught the virus from pet prairie dogs that had been housed near imported small animals from Ghana.
What’s different this time?
This is the first time monkeypox appears to be spreading among people who did not travel to Africa. Most of the cases involve men who have had sex with other men.
In Europe, infections have been reported in Britain, Italy, Portugal, Spain and Sweden.
Britain’s Health Security Agency said its cases are not all connected, suggesting that there are several paths of transmission happening. The infections in Portugal were picked up at a men's sexual health center.
On Wednesday, U.S. officials reported a case of monkeypox in a man who had recently traveled to Canada, where officials are investigating suspected infections in the Montreal area.
Is monkeypox spreading through sex?
Monkeypox has not been documented to spread through sex. But it can be transmitted through close contact with infected people, their body fluids and their clothing or bedsheets.
Michael Skinner is a virologist at Imperial College London. He said it is still too early to say how the men in Britain were infected.
Skinner told the Associated Press, “By nature, sexual activity involves intimate contact, which one would expect to increase the likelihood of transmission.”
Jimmy Whitworth is a professor of international public health at the London School of Hygiene and Tropical Medicine. He told Reuters that the new cases of monkeypox were "highly unusual" but urged people not to worry.
"This isn't going to cause a nationwide epidemic like COVID did, but it's a serious outbreak of a serious disease – and we should take it seriously," Whitworth said.
I'm Caty Weaver.
Maria Cheng reported the story for The Associated Press. Hai Do adapted the story for Learning English.
Words in This Story
endemic - adj. growing or existing in a certain place or area
mild - adj. not extreme or severe
symptom - n. a sign of sickness
rash - n. an eruption on the skin, usually flat
isolate - v. to keep in a place that is separate from others
transmission - n. an act or process of spreading or passing along
intimate - adj. marked by a warm friendship and close physical connection