RESUMO
Embryonated chicken eggs were inoculated with reticuloendotheliosis virus (REV), and the hatched chicks were reared until the age of 6 months. These birds were found to be viraemic and remained so for the entire duration of the experiment. In agar gel precipitation tests (AGPT) their sera reacted as REV antigen. Infective REV was demonstrated in these sera by inoculation of cell cultures or chickens. The viraemic birds responded poorly to Newcastle disease vaccine. Using the AGPT, a number of birds with REV antigen in their sera could be detected, in addition to the birds with REV antibody, in both turkey and chicken field flocks.
RESUMO
Turkey meningo-encephalitis virus could be adapted to the Japanese quail by intra-cerebral inoculation. After 4 passages the virus was found to be less pathogenic for the turkey. Further attenuation could be achieved by growing the virus in Japanese quail kidney cell cultures for 11 passages. This attenuated virus was used for the preparation of a live vaccine against turkey meningo-encephalitis. The safety and efficacy of the vaccine was shown in laboratory and field experiments.
RESUMO
The distribution of turkey meningo-encephalitis virus in infected birds and the development of immunity were studied. The turkey meningo-encephalitis virus was present in the blood as early as 24 h after experimental inoculation, and persisted for 5-8 d. Antibodies could be detected about the 5th d. A good correlation was found between haemagglutinin-inhibiting and virus-neutralizing antibodies. The virus could not be reisolated from any blood or organ sample collected after the 14th d and no sign of latent infection or carrier state could be found. The infection did not spread from the inoculated turkeys to control un inoculated birds in close contact. The possible existence of a natural reservoir and an arthropod vector of this virus is discussed.
