Rare monkeypox outbreak in U.K., Europe and U.S.: What is it and should we worry?

There's a monkeypox outbreak in the United Kingdom, Portugal, Spain and other European countries. The outbreak is small — so far 68 suspected cases, including eight in England and 20 in Portugal. Cases in Canada and a case in the U.S. have also been reported.

But health officials have little clue where people caught the monkeypox virus. And there's concern the virus may be spreading through the community — undetected — and possibly through a new route of transmission.

"This [outbreak] is rare and unusual," epidemiologist Susan Hopkins, who's the chief medical adviser of the U.K. Health Security Agency (UKHSA), said in a statement on Monday.

"Exactly where and how they [the people] acquired their infections remains under urgent investigation," the agency said in the statement.

Monkeypox can be a nasty illness; it causes fever, body aches, enlarged lymph nodes and eventually "pox," or painful, fluid-filled blisters on the face, hands and feet. One version of monkeypox is quite deadly and kills up to 10% of people infected. The version currently in England is milder. Its fatality rate is less than 1%. A case generally resolves in two to four weeks.