Aerosol immunization against Newcastle disease

The NDV-6-strain was selected by Lomniczi from naturally occurring Newcastle-disease-virus-strains. This strain was administered to chicken of different ages without detrimental effects. The strain was thermoresistant and adapted by serial passages in gut epithelial cells (NDV-6/10 variant). By using an aerosol of this strain (10(7),(3) EID50/m3) more than 1,3 millions chicken were immunised either in the incubator and up to an age of 10 days. Vaccine reactions were not observed. Vaccination against Marek's disease did not interfere with NDV-vaccination efficacy when day-old chicken were vaccinated with the NDV-6/10 aerosol. Obviously, the vaccine elicits a distinct cell-associated immunity. This explains, why chicken exhibiting low hemagglutination inhibition serum-antibody titers were found resistant to challenge infection with velogenic NDV. Immunity of chicken which have been vaccinated within 1 to 8 days post hatch by the NDV-6/10 aerosol vaccine, persisted 6 to 8 weeks and can be extended by revaccination up to onset of laying. The vaccine is now commercially available and designated VITAPEST.