In Asia and Africa (with the exception of some areas in southern Africa), the domestic dog is the main “reservoir” for rabies. Usually, there is only one reservoir host population for rabies in any given area, and controlling the disease in this population results in its disappearance from all other species. This has been shown with the elimination of rabies following oral vaccination of foxes in Western Europe, where red foxes (Vulpes vulpes) are the reservoir host.
Research projects in eastern Africa prove that mass vaccination of domestic dogs, even in areas (such as the Serengeti ecosystem) that comprise a wide diversity of wildlife species, reduces rabies significantly. When a sufficient percentage of the domestic dog population is vaccinated (70%), rabies also declines in wildlife species and human exposures to the rabies virus are significantly reduced.
Even when rabies is not controlled in wildlife, dogs are often the animals that transmit rabies to humans. So, vaccinated dogs can and do form a barrier to protect humans from rabies exposure.