Smallpox and monkeypox in non-human primates

In considering global eradication of smallpox the absence of an animal reservoir is important. Present knowledge of experimental infection of non-human primates with variola virus and of a related virus infection in monkeys, termed monkeypox, is examined.From the literature review and the results of a survey of captive monkeys in 26 major biological institutions it is concluded that outbreaks of supposed smallpox and monkeypox are not frequent and that man may be comparatively insusceptible to monkeypox. A natural reservoir of smallpox in non-human primates is thought to be unlikely although further studies are warranted since the survey reveals that certain species of monkeys can be infected with smallpox and that infected monkeys can transmit infection to others.