Aujeszky's disease virus eradication campaign successfully heading for last stage in the Netherlands

The Aujeszky's disease virus (ADV) eradication campaign in the Netherlands is based on compulsory vaccination and certification of ADV-free herds and consists of three stages: reduction of transmission of ADV, tracing and eli mination of remaining sources of ADV, and, in the last stage prohibition of vaccination. This paper summarizes the progress made in the first two stag es of the eradication. Between 1994-1999, ADV seroprevalence decreased shar ply in all four regions in the Netherlands, both in the sow and the finishi ng pig population. In the sow population, the mean ADV prevalence in the no rthern, eastern and western regions decreased to less than 0.5% in the firs t quarter of 1998, and to approximately 1% in the southern region. For the finishing pig population, the mean ADV prevalence decreased to less than 0. 6% in all fourregions in the first quarter of 1998, The proportion of sow h erds that were certified ADV-free increased steadily from approximately 40% in the last quarter of 1996 to 96% in the first quarter of 1999, The propo rtion of finishing pig herds that were certified ADV-free showed the same s pectacular increase as in the sow population: from approximately 14% in the last quarter of 1996 to 90% in the first quarter of 1999, It is anticipate d that the last stage of the ADV eradication campaign, stopping vaccination , will be achieved very soon. Monitoring wild boars for ADV between 1994 an d 1999 indicated that ADV is uncommon within the wild boar population. Ther efore, it seems that ADV infection in the wild boar population is not an im portant reservoir in the Netherlands.