Rabies is the oldest known infectious disease, for thousands of years this viral disease has haunted mankind. The present European rabies enzootic began in Poland in 1939 and advanced rapidly across Europe to conquer most regions in the continent within a few decades.
First stepsThe red fox was the main reservoir of this epidemic. 72 % of all reported cases between 1977 and 1997 were foxes. To control rabies, it became necessary to control fox rabies first. It was thought that fox rabies could be controlled by substantially reducing the population density of foxes, with the result that hundreds of thousands of animals were killed to try and stop the spread of the disease. With a few exceptions, all these methods failed to reduce the incidence of rabies or even halt its spread. Oral Vaccination as a Break-ThroughIn the early 1970s, American scientists showed for the first time that foxes could be immunized with attenuated virus vaccines. A subsequent break-through was the observation that animals could be vaccinated with these vaccines via the oral route. With the advent of the machine-made Tübingen bait in 1985, mass production of baits and thus large-scale vaccination programmes became possible. Now, more than twenty years later, oral vaccination of wildlife has been developed as the method of choice in Europe and North America. | Vaccination CampaignsThere is no doubt that the results obtained with oral vaccination are impressive. The incidence of rabies has decreased drastically in countries where our vaccine baits have been distributed. In some of these countries terrestrial wildlife rabies has been completely eradicated through oral vaccination campaigns, e.g. Italy, the Netherlands and Finland. The assessment of oral vaccination campaigns in terms of efficacy is, however, complex, because the incidence of rabies in vaccinated regions is influenced by many factors - the size of vaccination area, bait density, vaccination frequency, rabies situation, fox density etc. Baiting StrategiesOn the basis of our past experience we not only deliver the vaccine bait but work closely with the veterinary authorities and research institutes in setting up a long-term control programme. Large-scale and continuous vaccination campaigns are recommended, with a stepwise extension of the vaccination area, using the reduced infection pressure from the regions already treated. |
