Immunization of chickens against adenovirus infection

Chickens were vaccinated with monovalent and polyvalent adenovirus vaccines using three different serotypes, types 1, 2, and 3. No cross-protection was elicited by the heterologous serotypes but satisfactory protection from lesions and the shedding of challenge virus was induced by the homologous serotypes in the monovalent and polyvalent vaccines. The virus neutralizing (VN) titers were occasionally lower where the polyvalent vaccines were used when compared to those from chickens given the monovalent vaccines. This suggested possible interference though protection did exist against the appearance of lesions. Where chickens were vaccinated at an early age and in the presence of congenital homologous VN antibodies, protection against the effects of infection was satisfactory whereas the VN antibody titers were low or insignificant by the assay methods employed. The vaccine virus was not shed beyond 28 days after vaccination. No physical effects of vaccination were noted in any of the chickens during the post-vaccination period.