cowpox /kou″poks/ [AS, cu + ME, pokkes] , a mild infectious disease characterized by a pustular rash, caused by the vaccinia virus. Animals that carry the vaccinia virus are cows, cats, and rodents. Human cases are usually rare. Transmission to humans can occur during the milking of a cow with active lesions on the udder and teats, but the disease is usually transmitted by domesticated cats. Cowpox infection usually confers immunity to smallpox, because of the similarity of the variola and vaccinia viruses. Also called cat pox. See also smallpox, vaccinia.
