Antibody reaction to inhalation vaccination of poultry against Newcastle disease]

Aerosol preparated from the AVIPEST vaccine by means of three types of aerosol generators was used for vaccination of 294 chickens of different age against the Newcastle disease in laboratory tests and 30 000 chickens at the age of two and three weeks under field conditions. The general and local antibody reactions to vaccination were evaluated on the basis of the determination of the content of hemagglutination-inhibition and neutralization antibodies in the blood serum and in respiratory-tract flushings. The level of secretory antibodies in the flushings from the respiratory tract, determined by the described original method, is an important parameter of the resistance level of the organism to infection. The highest average levels of antibody titres in serum and in flushings were obtained 14 to 21 days from vaccination (7-10 log2). The La Sota vaccination strain was eliminated from the organism after spray vaccination and immunized the non-vaccinated contact chicken. Revaccination increased and greatly prolonged immunity. All the chickens inoculated showed resistance to challenge infection whereas the control birds died within four to six days.