Cowpox

Overview
Cowpox (also known as Catpox) is a disease of the skin that is caused by a virus (Cowpox virus) that is related to the Vaccinia virus. The ailment manifests itself in the form of red blisters and is transmitted by touch from infected animals to humans. The virus that causes cowpox was used to perform the first successful vaccination against another disease, smallpox, which is caused by the related Variola virus. Therefore the word "vaccination" has the Latin root vacca meaning cow.

The first vaccination was performed in 1774 by a farmer, Benjamin Jesty, in Dorset, England. He inoculated his wife and two young sons and thus spared them probable death by smallpox which was raging in the area in which they lived. His patients who had contracted and recovered from cowpox (mainly dairymaids), a disease similar to but much milder than smallpox, seemed to be immune not only to further cases of cowpox, but also to smallpox. By scratching the fluid from cowpox lesions into the skin of healthy individuals, he was able to immunize those people against smallpox.

However, credit was stolen by the politically astute Dr. Jenner who performed his first inoculation, having heard of Jesty's work, 22 years later. Even today he is falsely credited with the first vaccination.

The term vaccination was first used by Edward Jenner (an English physician) in 1796.

The virus is found in Europe and mainly in the UK. Human cases today are very rare and most often contracted from domestic cats. The virus is not commonly found in cows; the reservoir hosts for the virus are woodland rodents particularly voles. It is from these rodents that domestic cats contract the virus. Symptoms in cats include lesions on the face, neck, forelimbs, and paws, and less commonly upper respiratory tract infection. Symptoms of infection with cowpox virus in humans are localized, pustular lesions generally found on the hands and limited to the site of introduction. The incubation period is 9-10 days. The virus is prevalent in late summer and autumn.

Historical use
Cowpox was the original vaccine of sorts for smallpox. After infection with the disease, the body (usually) gains the ability of recognizing the similar smallpox virus from its antigens and so is able to fight the smallpox disease much more efficiently. The vaccinia virus now used for smallpox vaccination is sufficiently different from the cowpox virus found in the wild as to be considered a separate virus. Cowpox got its name from cow maids touching the udders of infected cows.