When our ancestors moved out of the African forest onto the savannah more than a million years ago, they rapidly became effective predators. Sharing prey with pre-existing carnivores, they acquired tapeworms that originally inhabited only hyenas, large cats, and African hunting dogs.
对人类而言，艾滋病、埃博拉、西尼罗河病毒和禽流感只是无数EID’s中最新出现的几种。一百万年前，当我们的祖先从非洲丛林搬迁至大草原时，他们很快就成为了战斗力极强的肉食动物。由于和那些早就存在的肉食动物一起食用猎物，他们得上了原先只在狼狗、大型猫科动物和非洲猎狗身上才会寄居的绦虫。