A little-known disease called monkeypox – a virus related to smallpox but less severe – has been reported in the U.S., Canada and other nations, health officials say. The infections have raised concern, because monkeypox is usually not found outside Africa. But the disease still considered extremely rare. The Centers for Disease Control and Prevention said the number of reported cases is above normal, but "the general public should not be concerned that they are at immediate risk for monkeypox." And though the outbreak is considered serious, monkeypox won't cause a national epidemic like COVID-19, USA TODAY reported. The virus is called monkeypox because it was first identified in laboratory monkeys in 1958, Nature reported. Human monkeypox was first found in the Democratic Republic of the Congo in 1970. The first U.S. case is a Massachusetts man who tested positive May 18 after returning from a trip to Canada, the CDC said. A second case is suspected in New York City. The CDC is also tracking cases in Europe. Person-to-person transmission is usually through close contact with respiratory secretions, inflected skin lesions or recently contaminated objects, according to the World Health Organization. Smallpox vaccinations are about 85% effective in preventing monkeypox infection, WHO said. Read more about the rare disease at the link in our bio.