[Recent studies on Aujesky's dissease in pigs and cattle (author's transl)]

A standardized test model for Aujeszky disease (AD) vaccines in pigs is described. The first two vaccines tested, a modified live virus (MLV) vaccine and an inactivated vaccine, failed to produce satisfactory results. The inactivated vaccine induced a short-lived, but clear-cut increase in body temperature in some of the vaccinated pigs; the MLV-vaccine was shown to spread. Complete protection against intranasal (i.n.) challenge was not achieved with either vaccine in five-month-old pigs that had been vaccinated once or even twice two to three months previously. However, the vaccinated pigs were less severely affected, and for shorter periods, than were the control animals; losses from death did not occur. In the control groups, at least thirty per cent died, the average growth of the remainder was arrested for more than three weeks. The mean period of arrested growth after challenge of pigs vaccinated once with the MLV-vaccine was slightly shorter than that following a single vaccination with the inactivated vaccine: 5.8 and 9.5 days respectively. The average virus excretion of vaccinated pigs after challenge was less and was not as protracted as in unvaccinated controls. In pigs from sows hyperimmunized with the inactivated vaccine, maternal antibodies afforded partial protection against i.n. challenge at the age of two months. However, five-month-old pigs were fully susceptible, although most of them continued to show low levels of neutralizing antibody. The average virus excretion after challenge in the two age-groups was comparable with that in control pigs. Cattle were effectively protected by vaccination with the inactivated vaccine against i.n. challenge with AD-virus. It is recommended to vaccinate "threatened" cattle twice, for instance in the autumn when they are removed from the pastures for indoor housing. The possibility that temperature reactions may occur should be taken into account.