Zoonotic diseases present challenges not only to veterinarians but also to all professions concerned with public health. Cooperation between veterinarians and public health physicians has been an important factor in zoonosis control programs. An example of this collaboration is the eradication of bovine tuberculosis, first in Denmark, Sweden, Finland, and Norway, and then in the USA, Canada, and other countries. Unfortunately, some zoonoses that are well controlled in developed nations, such as bovine and porcine brucellosis, bovine tuberculosis, and rabies, remain major problems in the developing world. Diseases can also reemerge in areas where they have been eradicated. Newly recognized zoonotic organisms such as Hendra and Nipah viruses are emerging, and many other zoonoses remain a constant concern.