Attempts to immunize monkeys against experimental infection with Herpesvirus suis

Attempts were made to immunize grivet monkeys by intranasal administration of 2 doses of the avirulent Bartha strain of Aujeszky's disease virus (ADV). They were later challenged by the same route with virulent ADV. Vaccination failed to provide any protection and all the animals died of encephalomyelitis 9 to 14 days after infection. The clinical disease was more prolonged than in non-immunized monkeys, but the nature of the histological lesions and their distribution in the brain were the same.