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Duck viral hepatitis type 1 vaccination: monitoring of the immune response with a microneutralisation test in Pekin duck embryo kidney cell cultures.

A microneutralisation test in Pekin duck embryo kidney cell cultures with attenuated duck hepatitis virus (DHV) type 1 is described for monitoring and evaluating the immune response following vaccination of Pekin ducks against duck hepatitis type 1. Serum samples from 19 flocks of commercial fattening ducks 7 to 8 weeks of age had no detectable antibodies. Breeding ducks experienced exposure to DHV type 1 during the growing period as evidenced by some positive reactions in the VN test. Two consecutive subcutaneous vaccinations prior to the first breeding season resulted in high, and in most cases, uniform titres against DHV with small standard deviations and mostly narrow 95% confidence limits of the respective mean values. Additional vaccinations prior to further breeding seasons did not result in augmentation of the humoral immune response.