cow.pox
n.（名词）A mild, contagious skin disease of cattle, usually affecting the udder, that is caused by a virus and characterized by the eruption of a pustular rash. When the virus is transmitted to humans, as by vaccination, it can confer immunity to smallpox.Also called vaccinia 牛痘：牛的一种良性皮肤传染病，通常感染乳房，由一种病毒引起并出现发脓疱疹症状。当这一病毒通过种痘等被移植入人体后，它可以产生对天花的免疫力也作 vaccinia
