Bernard Toma

Epidemiology of Fox Rabies

Publisher Summary Despite the availability of more effective and less harmful vaccines for the protection of humans and animals, rabies remains a very widespread disease in the world transmitted by both domestic and wild animal vectors. Dogs, especially stray dogs, are responsible for maintaining the enzootic in most of the countries of Africa and Asia, where veterinary and sanitary structures are inadequate. Certain wild animals, particularly vampire bats, are the reservoirs of perennial rabies in vast zones of Central America and South America. In other areas, notably of Europe, where animal rabies control can be effectively applied and where there is practically no rabies infection of bats, another species of wild animal has taken the place of the dog as preferential vector of rabies during the last decades: the fox. In most European countries, there has been a progressive inversion in the frequencies of canine rabies and vulpine rabies to the advantage of the latter. This change seems to be taking place within the framework of a general increase in the density of the fox population that, if one accepts the hunting statistics of certain countries, has at present reached a level two to four times higher than at the beginning of the century. This has been due to the diverse factors, such as the elimination of natural enemies of the fox, the changes in hunting practices or of the agricultural techniques, and the like. The methods used to fight vulpine rabies are much more difficult to apply than are available methods for eradicating canine rabies and the results are far more hazardous. Therefore, countries, in which the standards of livestock maintenance are excellent and have successfully eliminated all the other great contagious animal diseases, are still powerless to limit the expansion of rabies. This problem is directly related to the density of the fox population. There has been a great deal of research during the past 15 years on the epidemiology of fox rabies and the possible measures of prophylaxis against it. The results have begun to accumulate and one can now attempt to present a synthesis of the essential ideas.