Systematic Veterinary Virology

VACCINATION

• Immunization of breeder ducks with modified live virus vaccines, using Types I, II, and III viruses, provides parenteral immunity that effectively prevents high losses in young ducklings. The Type I virus vaccine is administered SC in the neck to breeder ducks at 16, 20, and 24 wk of age and every 12 wk thereafter throughout the laying period. The three immunizations are advisable for passive protection of ducklings.
• Inactivated vaccines against DHV I can also be used in primed ducks, which give high antibody titre.
• The chick-embryo origin, modified live Type I virus vaccine also can be used for early vaccination of ducklings susceptible to Type I (progeny of nonimmune breeders). This vaccine is administered SC or by foot web stab in a single dose to day-old ducklings. These ducklings rapidly develop an active immunity over 3-4 days.