The greatest single concern regarding foxes today is their potential to spread rabies. Rabies is a disease of the nervous system found in warm blooded animals, frequently found in bats, foxes, raccoons, and skunks. It is spread through the exchange of body fluids between animals, most frequently being transmitted by saliva when an infected animal bites. As the disease progresses, the infected animal may exhibit behavioural changes varying between apathy and aggression. Muscular coordination is increasingly impaired and the animal eventually dies. Rabies is fatal in humans unless treated immediately, and can wreak havoc amongst pets and live stock. As a result, rabies is greatly feared, and foxes have been subject to massive extermination campaigns in several attempts to control the disease.

Efforts to control rabies through such extermination programs have proven to be less than successful. First, the elimination of predatory species such as foxes, coyotes, and wolves have frequently caused environmental and agricultural consequences worse than the disease itself. Secondly, foxes have shown amazing resilience in the face of these campaigns, rapidly reasserting themselves as soon as the killing ends. And third, the destruction of healthy fox populations only encourages infected animals to immigrate from abroad. Clearly a more effective alternative to trapping had to be developed.

The preferred method of rabies control today is through mass vaccination of susceptible populations. Switzerland first tried this innovative method in 1978 by putting vaccine into chicken heads and spreading them over the Rhone River Valley. Once a fox eats the chicken head, it is inoculated against the disease. The program was an outstanding success and has practically eliminated rabies from that country. Because of the limited availability and perishability of chicken heads, a new bait has been developed, made from fat, fishmeal and bone meal. The vaccine is than easily distributed from the air over effected areas. Several countries have reported significant reductions in this disease through the use of these aerial bombardments.

In "Red Fox: The Catlike Canine", J. David Henry points out that vaccination programs such as these may prove unsuccessful in urban environments. Food resources in these areas are plentiful, and in some cases up to 70% of a fox´s diet can come from handouts from friendly humans. Given that 90% of a fox population must be inoculated to be of any use, and less than 40% of these urban animals are receptive to taking baits, it´s obvious that new baits and inoculation methods are going to have to be developed. Nevertheless, programs such as these show a much more enlightened and effective approach to this centuries old problem.