2 Strains of Monkeypox Found in US

Genetic analysis of recent cases of monkeypox suggests that there are two different strains in the United States, health officials said on Friday, that the virus may be circulating undetected for some time. 

Many cases in the United States were caused by the same strains as recent cases in Europe, but some samples show different strains, federal health officials said. Each strain was seen in a US case last year before a recent international outbreak was confirmed.

More patient analysis is needed to determine how long monkeypox circulates in the United States and elsewhere, says Jennifer McQuiston of the Centers for Disease Control and Prevention.

Monkeypox usually begins with a flu-like illness and swollen lymph nodes, followed by a rash on the face and body. The disease is endemic in parts of Africa where humans are bitten and infected by rodents and small animals.

Cases have occurred in Europe and the United States over the past month. Many, if not all, people infected with the virus are traveling abroad and are being investigated by health authorities in more and more countries.

As of Friday, the United States has identified at least 20 cases in 11 states. Hundreds more cases have been found in other countries, many of which appear to be associated with sexual activity in two recent raves in Europe.