[Progress in the development of vaccines against Aujeszky's disease].

New insights into the molecular biology of pseudorabies virus (PrV), the causative agent of Aujeszky's disease (AD) of pigs, led to novel concepts for eradication of the disease. Virus mutants, which lack certain nonessential glycoproteins, formed the basis for the development of the first available marked vaccines. They allow a differentiation between infected and vaccinated animals. Further molecular studies resulted in the identification of several PrV genes whose products modulate virulence and pathogenicity of the virus, and which are therefore targeted by genetic engineering methods to develop new attenuated virus strains. The isolation of virus mutants, which cannot be shed in infectious form by vaccinated animals, led to an increase in the biological safety of respective PrV vaccines. The availability of these mutants now provides the basis for the development of safe PrV vector vaccines, in which recombinant PrV express immunogenic proteins of other, unrelated viruses leading to a broad antiviral immunity. Based on PrV vectors marked vaccines against other viral diseases are being developed which represent powerful tools for combatting infectious diseases in animals.