User:Coffin22/sandbox

Stages of zoonosis
Zoonotic pathogens can be categorized into several stages based on their degree of association with their animal and human hosts. Pathogens like rabies use humans as hosts only incidentally, generally not being transmitted beyond their first human host. On the other extreme, some pathogens such as HIV-1, have completed their zoonosis[cite] and are now found exclusively in humans. Many pathogens are in between these extremes: yellow fever has frequent zoonosis events followed by localized secondary human to human infections.