Infectious Bursal agent of chickens reduces the incidence of lymphoid leukosis

In tests to determine whether infectious bursal agent (IBA) would significantly affect the incidence of lymphoid leukosis (LL), chickens were inoculated with an LL virus and subsequently exposed to IBA at 2 weeks or 8 weeks of age. When chickens were exposed to IBA at either age, the IBA significantly reduced the incidence of LL without affecting the chicken's ability to produce antibody to sheep erythrocytes. IBA probably destroys the target cells necessary for the development of LL tumours. It is postulated that IBA may play a role in the field incidence of LL.