Cowpox refers to a disease that is caused by the cowpox or catpox virus. The virus is a member of the orthopoxvirus family. Other viruses in this family include the smallpox and vaccinia viruses. Cowpox is a rare disease, and is mostly noteworthy as the basis of the formulation, over 200 years ago, of an injection by Edward Jenner that proved successful in curing smallpox.

The use of cowpox virus as a means of combating smallpox, which is a much more threatening disease to humans, has remained popular since the time of Jenner.

Once a relatively common malady in humans, cowpox is now confined mostly to small mammals in Europe and the United Kingdom. The last recorded case of a cow with cowpox was in the United Kingdom in 1978. Occasionally the disease is transmitted from these sources to human. But this is very rare. Indeed, only some 60 cases of...