Where do we stand with oral vaccination of foxes against rabies in Europe?

Abstract

The oral vaccination of wild animals was first attempted in 1962 after the repeated failure of poisoning or trapping to control movement of the disease in these species. Foxes were chosen for research purposes because they are a problem animal species and are exquisitely susceptible to rabies. The first successful laboratory studies with attenuated vaccine came in 1971, and the first successful field trial was carried out in Switzerland beginning in 1978. In the 1980’s several European countries joined the trials. In the following years many improvements were made: the chicken head was replaced by machine-made baits for easy mass production, the hand placement of vaccine baits was to a greater extent being replaced by aerial distribution (small aircraft or helicopter), and several new vaccines were developed. Additionally, the European Union supported the oral vaccination financially. There was a great impact on the rabies situation. When the second country, Germany, joined the field trial in 1983 the total of reported rabies cases in Europe amounted to 23 002, in 1995 a total of 8 134 cases was reported. In spite of the great improvement made in the past years, in the beginning of the 1990’s several severe set-backs were experienced. The paper elaborates on reasons for these set-backs and suggests a strategy to overcome them.