Assessment of the immune response to duck plague vaccinations.

An experiment was conducted to assess the immune responses of ducks to duck plague (DP) vaccinations employing one commercial and one laboratory-adapted (LA) DP vaccines. Virus neutralisation and leucocyte migration-inhibition tests were conducted at regular intervals before and after vaccinations. Similarly, ducks in vaccinated and control groups were subjected to challenge infection with virulent DP virus. The commercial vaccine yielded a poor immune response and partial protection on challenge whereas satisfactory responses were obtained in ducks receiving two doses of LA vaccine. The humoral as well as cellular factors were stimulated indicating possible involvement of both the immune responses in the protection from duck plague.