Control and eradication of Aujeszky's disease: an assessment of the scheme in Northern Ireland

Abstract

Aujeszky's disease (AD) is an important disease affecting the swine industry in many countries. An eradication catnpaign was officially applied in September of 1994 in Northern Ireland. The current eradication scheme was investigated.

Two main groups of herds were identified from an existing computed database and were classified as: group A, herds that changed their health status, and group B herds that did not change their health status. Herds within each group (A and B) were also classified according to their health status into two groups: a) Otliers, herds that were neither infected nor vaccinated and regarded as free of the disease, and b) PS's, herds that were either vaccinated and/or infected.

The eradication scheme in Northern Ireland is making progress. The linear regressions on months were significantly for the number of herds (F=29.14, P<0.05), and the high health status OADF (F=91.5, P<0.01) and ADF(F= 167.8, P<0.001). More herds had higher health status in tl1an before. Infected herds decreased from 25 % to 10.7 % after two years. In addition the pig industry expanded with new herds being registered, although their disease status has yet to be assessed. The groups of herds were analysed by region, current status, herd type and pig population The main significant difference in the number of herds was found for the comparisons between the groups 1) Others and PS's (X²= 116.9, P<0.001), 2) PS1 +PS2 and PS3+PS4 (X²=3.73, P<0.05), and 3) PS1+PS3 and PS2+PS4 (X²=5.68, P<0.01) of group A and group B when compared together. It was identified that the most important regions in terms of number of infected herds, pig population and new herds awaiting classification of their health status were UK3 and UK4 where more than 50% of infected herds were found in these two regions that share borders.