POLYMERASE CHAIN-REACTION AMPLIFICATION OF LATENT AUJESZKYS-DISEASE VIRUS IN DEXAMETHASONE-TREATED PIGS

A polymerase chain reaction (PCR) amplification assay was developed fo r the detection of Aujeszky's disease virus (ADV) DNA in cell cultures and clinical samples. Pigs vaccinated with commercial ADV vaccines an d challenged with a field isolate of ADV were immunosuppressed by dexa methasone treatment. Nasal swabs collected from the pigs at various ti mes post-immunosuppression showed that ADV was excreted for at least f our to six days starting from day 8 or day 10 following dexamethasone treatment, by virus isolation and/or PCR. However, PCR only detected l atent ADV in the trigeminal ganglia, mandibular lymph node, spleen and tonsils, but not in the brain stem, pens and olfactory lobe of two pi gs following dexamethasone treatment, whereas tissue explanation and c ocultivation failed to demonstrate the presence of the virus.