CARRIER ANIMALS IN A DANISH HIGH-HEALTH MULTIPLYING HERD RECENTLY INFECTED WITH ACTINOBACILLUS PLEUROPNEUMONIAE SEROTYPE 2

摘要

Actinobacillus pleuropneumoniae (AP) serotype 2 is the predominant serotype of AP in Denmark. High-health herds are monitored for freedom of this disease by serological analyses and clinical inspections. However, the presence of seronegative, clinically asymptomatic animals, carrying AP in their tonsils is an aspect not included in this monitoring. These animals pose a risk for introducing disease when new stock is brought into a herd. If the tonsil carriers do not have any detectable antibodies to AP the currently used control methods might be insufficient. The primary objective of this study was to follow carrier animals (clinically asymptomatic, seronegative, tonsil-positive animals) from the age of 8 weeks until slaughter to evaluate to which extent and for how long the animals remained seronegative.