Cowpox (also known as Catpox) is a isease of the skin that is caused by a virus known as the Cowpox virus. The pox is related to the vaccinia virus, and got its name from cow maids touching the udders of infected cows. The ailment manifests itself in the form of red blisters and is transmitted by touch from infected animals to humans.When it is gone,the person is immune to smallpox.