Eradication of Aujeszky's disease from a large-scale pig farm.

Eradication of Aujeszky's disease from a large-scale pig farm by the 'test-and-cull' eradication procedure based on the use of gene-deleted vaccines and serological monitoring using gE ELISA is described. Aujeszky's disease free status was successfully achieved on a farrow-to-finish type farm characterised by three difficulties interfering with the success of eradication: (i) weaned (30-day-old) piglets remained in the farrowing house until 65 days of age; (ii) the farm did not use nursery rearing; (iii) fatteners were kept together with the breeding gilts. Thus, the immunisation programme had to be adjusted to the management technology used on the farm, and by regular serological monitoring it had to be periodically modified to make it suitable for attaining the goals. This meant that breeding animal candidates of a wide age range and kept in the same air space had to be provided with a continuously high-level immunity by regular vaccination sufficient even for rectifying potential human errors. The immunisation programme was designed by taking into consideration the disappearance of maternal immunity, and a strict vaccination programme was applied during the rearing of breeding gilts kept together with the fattening pigs. Frequent immunisation applied during the rearing of the own breeding animal replacements proved to be of decisive importance for the eradication of Aujeszky's disease from the entire herd. In addition to the accurate implementation of the vaccination programme, regular serological monitoring also made a major contribution to the success of eradication.