Influence of Passive Immunization on Active Immune Response of Ducklings to Duck Hepatitis Virus Vaccine

  • Trần Thị Lan Hương

Abstract

Effects of passive immunization of ducklings were evaluated using a challenging method. The offsprings of laying ducks which were vaccinated with duck hepatitis virus vaccine showed high level of specific antibody at 1 day old and then decreased. At 15 days of age, the ducklings from those ducks having laid for 1 month, the protective potential of passive immunity was approximately 30- 40%.  The level of passive immunity of ducklings from ducks having laid for 6 months could protect only 10 - 20% of challenged cases. Passive immunization against duck hepatitis virus also affected active immune response which was induced after the first boot of duck hepatitis virus vaccine. The optimal time for the first vaccine was determined as follow: (1) At 1 day old for ducklings having no passive immunity, 14 - 21 days after vaccination, the protective ratio against high pathogenic strain was 80%; (2) If ducklings had passive immunity, the first vaccine should be given at 7 days old, the ratio of protection was estimated to be up to 100% at 14 - 21 days after vaccination
điểm /   đánh giá
Published
2012-11-21
Section
Bài viết