NEW YORK (PIX11) — A medical mystery unfolded in New York City and across the country this week. Cases of monkeypox have popped up across several American cities and Europe. 

Doctors at Bellevue Hospital are treating a patient with what the health department classified as a possible case of monkeypox. The person is in isolation and tests have been done to determine if it is the rare virus typically spread in Africa. However, experts said there’s no need to be alarmed.

“It’s a really rare illness, especially in high-resource countries like the U.S.,” Dr. Anthony Santella, an infectious diseases expert, said. “Even if it’s confirmed, it’s not like people who rode the subway or were at a public place need to panic.”

Most patients with Monkeypox experience fever, body aches, chills and fatigue. Anyone who gets a more serious illness may develop the signature rash and lesions on the body. It can be deadly in 10% of cases and is more severe for children. Monkeypox is more commonly spread through infected wild animals.

The first U.S. confirmed case emerged earlier this week in Boston. The patient had just traveled to Canada. The last outbreak in the country was in 2003 when 47 people got the virus from imported prairie dogs.