Recombinant CowpoxVirus, CPXV A27 Protein

Cowpox is an infectious disease caused by the cowpox virus. The virus, part of the genus Orthopoxvirus, is closely related to the vaccinia virus. The virus is zoonotic, meaning that it is transferable between species, such as from animal to human. The transferral of the disease was first observed in dairymaids who touched the udders of infected cows and consequently developed the signature pustules on their hands. Cowpox is more commonly found in animals other than bovines, such as rodents. Cowpox is similar to, but much milder than, the highly contagious and often deadly smallpox disease. Its close resemblance to the mild form of smallpox and the observation that dairy farmers were immune from smallpox inspired the first smallpox vaccine, created and administered by English physician Edward Jenner.

Vanessa Ngan, "Viral and Skin Infections", 2009. "What's The Real Story About The Milkmaid And The Smallpox Vaccine". NPR.org. Retrieved 2018-02-02. Thomas Cooper Library, University of South Carolina: "Edward Jenner and the Discovery of Vaccination", exhibition, 1996.