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 labora tory-adapted (LA) DP vaccines. Virus neutralisation and leucocyte migr ation-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 comm ercial vaccine yielded a poor immune response and partial protection o n challenge whereas satisfactory responses were obtained in ducks rece iving two doses of LA vaccine. The humoral as well as cellular factors were stimulated indicating possible involvement of both the immune re sponses in the protection from duck plague.