What is Cowpox?

Cowpox is a skin and viral disease caused by the cowpox virus. The disease, characterized by pockmarks similar to chickenpox, is related to contact with cows and is a relative of the vaccinia virus. The vaccinia virus was responsible for the smallpox virus and its cure in the 20th century. Less serious than the deadly smallpox, cowpox creates the same kind of mild symptoms as chickenpox. The disease is transmitted through direct contact with cows, horses or any other animal carrying the disease, and appears on human skin as the rash or red blisters common to other pox diseases.

Deriving its name from the dairymaids who commonly transmitted the disease from touching cow udders, cowpox was used to help develop the vaccination for smallpox in 1979. Before that breakthrough, however, the history of human cowpox infection dates back to at least the 18th century. Testing for cowpox as a possible cure for smallpox began in 1791 when German teacher Peter Plett exposed his sons to the cowpox virus intentionally. This exposure thus saved them from the smallpox epidemic that was ravaging the area at the time. Cowpox, like chickenpox, can usually only be contracted once in a person’s life.

Today the disease is almost strictly confined to Europe, most notably in the UK, and is usually the result of contact with infected domestic cats. Despite its name, the disease is no longer common in cows, confining itself instead in woodland rodents such as mouse and similar creatures called voles. Through contact with these rodents, cats contract the virus and it manifests itself in the form of blisters and lesions on the skin of the cat.

Most prevalent in the summer and fall, the cowpox virus can be contracted only through direct contact with an infected animal. Many times the infected area on a human is only seen in the area of contact with the animal, and can be passed to other humans with further contact. The incubation period for the disease is around eight to ten days, and the blisters will generally alleviate themselves, often with minor scarring.

Cowpox, in its history as a cure or vaccine for smallpox, was used much like a flu shot is used today. With introduction of the virus into the human body, the immune system familiarizes itself with the smallpox virus and fights the weaker relative, making the system immune to similar viruses like smallpox or chickenpox.