Camelpox: A severe disease of camels in northern Africa and southwestern Asia caused by the camelpox virus. This virus has rarely, if ever, caused disease in people. However, the sequence of the camelpox virus genome is most closely related to that of the variola virus, the cause of smallpox. This has led to speculation that the two viruses (camelpox and smallpox) may have evolved from a common ancestor after the advent of intensive agriculture some 7,000 years ago. See also: Orthopox; Smallpox.