RESUMO
Contamination of 8 avian species with leukosis viruses was studied. An insignificant portion of sera from 4 and 24 months old chickens contained neutralizing antibody to 3 sero-types (A, B and D) of Rous sarcoma virus (RSV). Sera from guinea-fowl reacted positively in the neutralization test only with the RSV-RAV-1 strain. None of the Peking duck and semi-domestic Maran fowl sera was found to contain antibody to RSV strains. Twenty-five and 6.6% of embryos derived from 7-8 and 24 to 30 months old chickens respectively, 30% of liver specimens from 3-4 months old chickens 3.3% of liver specimens from adult guinea-fowl and 72% of liver specimens from Maran fowl contained the group-specific leukosis complement-fixing antigen (gs-antigen). Duck embryos and livers from 24-30 months old chickens, crows, sparrows, rooks or jackdaws contained no gs-antigen. Duck embryos did not react and ducklings reacted poorly to inoculation with RSV whereas guinea-fowl embryos and chickens proved to be highly susceptible to RSV.