Researchers at the University of Georgia have investigated the possible reasons why Arkansas infectious bronchitis vaccines are not effective when delivered by a hatchery spray cabinet, even though Massachusetts-type infectious bronchitis vaccines are effective when given by a hatchery spray cabinet and the Arkansas vaccines are effective when given by eye drop, according to WorldPoultry News.

Doctors Mark Jackwood and Brian Jordan found that, although the inefficient nature of delivering vaccines with a hatchery spray cabinet contributes to the problem, the failure of Arkansas IBV vaccine when delivery by a hatchery spray cabinet was not solely related to the mechanism of delivery but rather to problems inherent in the Arkansas vaccine.

The researchers said that Arkansas vaccines contain multiple virus subpopulations.  “One of the minor virus subpopulations in the vaccine is responsible for infecting the chickens and inducing immunity.  A sufficient amount of this minor subpopulation in the Arkansas vaccine capable must be be given for the vaccine to be effective.