Wikipedia the Free Encyclopedia
A zoonosis (pronounced /ˌzoʊ.əˈnoʊsɨs/) or zoonose is any infectious disease that can be transmitted (in some instances, by a vector) from non-human animals, both wild and domestic, to humans or from humans to non-human animals (the latter is sometimes called reverse zoonosis). Many serious diseases fall under this category.
The simplest definition of a zoonosis is a disease that can be transmitted from other vertebrate animals to humans. A slightly more technical definition is a disease that normally infects other animals, but can also infect humans. The reverse situation (transmission from human to animal) is known as anthroponosis.