Observations on the serological and dermal responses of turkeys to a single subcutaneous inoculation of inactivated Newcastle disease vaccine in mineral oil adjuvant.

Each of 10 growing turkeys given a primary subcutaneous inoculation of inactivated Newcastle disease vaccine in mineral oil adjuvant responded with the production of virus-neutralizing (VN) and haemagglutination-inhibiting (HI) antibodies. Biphasic modulation of the serological response was more evident with HI than with VN antibodies. At the inoculation site there developed a discrete swelling that regressed within the 10 week period of observation. Histologically the swelling consisted of an inflammatory granulomatous reaction, with an accumulation of macrophages containing phagocytosed droplets of vaccine. Plasma cells were also present. No inflammatory swelling developed in chickens and pheasants similarly vaccinated but comparable cellular changes were noted around the dispersed vaccine.