Here are 10 things we know about the Monkeypox outbreak:
Monkeypox is a rare viral infection which is similar to human smallpox. It was first discovered in 1958 in monkeys kept for research. The first human case of monkeypox was recorded in 1970.
Monkeypox can be caught from a bite by an infected animal, or by touching its blood, body fluids, or fur. It's thought to be spread by rodents, such as rats, mice, and squirrels. It's also possible to catch the disease by eating meat from an infected animal that has not been cooked properly.
Health officials have noted some of these infections may be transmitted through sexual contact. The WHO said it was also investigating that many cases reported were people identifying as gay or bisexual.
Fever, muscle ache, lesions, and chills are the common symptoms of monkeypox in humans
Canada was the latest country to report it was investigating more than a dozen suspected cases of monkeypox after Spain and Portugal detected more than 40 possible and verified cases. Sweden and Italy also reported its first case of monkeypox today.
The United States reported its first monkeypox case yesterday. A man in the eastern state of Massachusetts tested positive for the virus after visiting Canada.
Britain has confirmed nine cases since May 6.
According to the Centers for Disease Control and Prevention, there were no reported cases of monkeypox for 40 years before it re-emerged in Nigeria in 2017.
There's currently no specific treatment for monkeypox. Patients will usually need to stay in a specialist hospital so the infection doesn't spread and general symptoms can be treated.
The incubation period (interval from infection to onset of symptoms) of monkeypox is usually from 6 to 13 days but can range from 5 to 21 days, according to the WHO.