Monkeypox virus is an orthopoxvirus that causes a disease in humans with symptoms similar, but less severe, to those previously seen in smallpox. While smallpox was eradicated in 1980, monkeypox continues to occur in countries of Central and West Africa.

Monkeypox is a zoonosis, i.e. a disease that is transmitted from animals to humans. Cases are often found close to tropical rainforests where there is frequent contact with animals that carry the virus. Evidence of monkeypox virus infection has been found in many animals including rope squirrels, tree squirrels, Gambian poached rats, dormice, different species of monkeys and others.

Human-to-human transmission of the virus is limited, with the longest documented chain of transmission being six generations, i.e. meaning that the last person to be infected in this chain of transmission was six links away from the original sick person. The virus can be transmitted through contact with bodily fluids, lesions on the skin or on internal mucosal surfaces, such as in the mouth or throat, respiratory droplets and contaminated objects.

Detection of viral DNA by polymerase chain reaction (PCR) is the preferred laboratory test for monkeypox, given its accuracy and sensitivity. For this, the best diagnostic specimens are directly from the rash – skin, fluid, or crusts, or biopsy where feasible. Antigen and antibody detection methods may not be useful as they do not distinguish between orthopoxviruses