Human monkeypox: an emerging zoonosis

Abstract

Human monkeypox is a rare viral zoonosis endemic to central and western Africa that has recently emerged in the USA. Laboratory diagnosis is important because the virus can cause disease that is clinically indistinguishable from other pox-like illnesses, particularly smallpox and chickenpox. Although the natural animal reservoir of the monkeypox virus is unknown, rodents are the probable source of its introduction into the USA. A clear understanding of the virulence and transmissibility of human monkeypox has been limited by inconsistencies in epidemiological investigations. Monkeypox is the most important orthopoxvirus infection in human beings since the eradication of smallpox in the 1970s. There is currently no proven treatment for human monkeypox, and questions about its potential as an agent of bioterrorism persist.

Figure 1

African child with disseminated monkeypox. Note postauricular adenopathy (courtesy of Leo Lanoie, Prince Albert Parkland Health Region, Saskatchewan, Canada).

Figure 2

African woman with smallpox (courtesy of Department of Infectious and Parasitic Disease Pathology, Armed Forces Institute of Pathology, Washington, DC, USA)

Figure 3

Human monkeypox lesions adjacent to the site of primary inoculation in a child during the 2003 US outbreak (courtesy of Marshfield Clinic, Wisconsin, USA).

Figure 4

Human monkeypox lesions on the thorax of an adult male patient during the 2003 US outbreak (courtesy of Marshfield Clinic, Wisconsin, USA).

Figure 5

Geographical distribution of human monkeypox.

Figure 6

Electron micrograph depicting orthopoxvirus particles in a human skin biopsy from the 2003 US outbreak (courtesy of Marshfield Clinic, Wisconsin, USA).