Dry aerosol vaccination against Newcastle disease. I. Safety and activity controls on chickens.

A new technic or immunization against Newcastle disease in chicken was developed: this method consists of dispersing lyophilized products by aerosols. One to fourteen day old chickens, with and without parental antibodies, were vaccinated with increasing amounts (10(-1) to 10(5)EID50) of HB1 and LaSota attenuated viruses. 10(4)EID50, inhaled theoretical dose, gave better results when the animals were challenged with the virulent strain. Under laboratory conditions, no respiratory problems occurred in vaccinated animals; but there is 10 to 20% mortality among animals treated by aerosols in poultry houses, because of respiratory diseases developed after vaccination.