The detection of the big liver and spleen agent in infected tissues via intravenous chick embryo inoculation.

Partially purified homogenates prepared from the livers of birds affected with BLS were used to inoculate intravenously young adult broiler breeder hens and incubating chicken embryos. Following inoculation, the broiler breeders developed pathological and serological responses typical of BLS infection. The same antigen resulted in persistent antigenaemia in chickens which were inoculated during various stages of incubation. This technique was very sensitive and could be used for detection and titration of virus in tissue preparations. Methods for optimization of the technique were investigated. Chick embryos demonstrated the greatest susceptibility to agent replication when inoculated at 11 days of embryonation. After hatching, agent replication appears to increase with age. Inoculated chickens bled at 8 days of age showed increased incidence of antigenaemia by this procedure.