Emergencies preparedness, response

Human Monkeypox (MPX)

Monkeypox home page image.
Human Monkeypox, DRC 1984.
Marc Szczeniowski/WHO

Monkeypox virus (MPXV) is an orthopoxvirus that causes human monkeypox (MPX), a viral disease with symptoms in humans similar to that seen in smallpox patients. Smallpox no longer occurs, following its worldwide eradication in 1980, whereas human monkeypox is regularly reported in villages of Central and West Africa close to tropical rainforest where there is frequent contact with infected animals.

Monkeypox is usually transmitted to humans from non-human primates, squirrels or other rodents (e.g. Gambian rats) through contact with the infected animal’s blood or through a bite. Humans also acquire the disease through direct contact with infected patients but there is no evidence to date that person-to-person transmission alone can sustain MPX in the human population.

Latest update

In May-June 2003, MPXV was identified for the first time in the Western Hemisphere and was the cause of a cluster of cases of MPX in the US Midwest. The primary source of the US outbreak was thought to be native prairie dogs (Cynomys sp.) housed with rodents imported from Ghana in West Africa.

In November 2005, several MPX cases were reported in Bentiu, Unity State, Sudan. This was the first time MPX has been reported in a dry savannah environment in Africa.

For more information

WHO fact sheet

  • Monkeypox
    Available in Arabic, Chinese, French, Russian, Spanish

Contact information

Department of Pandemic and Epidemic Diseases
World Health Organization
Avenue Appia 20
1211 Geneva 27