Why is it important to know the red fox density?

GIF - 96.6 kb
Fox cub marking

The occurrence, epidemiology and spread of fox rabies are intrinsically tied to the abundance and population density of its reservoir species, the red fox. The perpetuation of rabies in the red fox occurs as the result of the interaction between the parameters of two major biological associations, e.g. the virus-host and host-environment relationships. Red fox densities are mainly affected by the carrying capacity of a given area as a result of food resources, habitat and other factors.

High population densities of susceptible hosts favour the incidence and the spread of rabies. Therefore, knowledge about the density of the fox population targeted in a given region can give some indication of the bait density and vaccination coverage needed for an ORV campaign to be effective. In areas with lower fox densities, fewer vaccination campaigns using lower bait densities in a more restricted area will be required every year compared to areas with higher fox densities.

In areas where baits have been distributed just after a rabies epidemic has reduced the fox density, fox rabies will be eliminated much faster than in areas with higher fox densities. In areas where foxes have been vaccinated for a number of years, the fox population is likely to increase as a result of ORV, and vaccination strategies may need to be adapted in order to eliminate rabies.

Therefore, wherever and whenever possible, consistent and persistent monitoring of the fox population should be an integral part of an ORV programme to guarantee maximum success within an appropriate timescale.


Home | Contact | Site Map |
Version 1 - Last updated November 2012