Immunological and serological studies on the viruses of fowl-pox and vaccinia

Abstract

Three strains of fowl-pox virus were studied; 2 were pathogenic for fowl only, and 1 for fowl and pigeon. All attempts to render these strains pathogenic for rabbits, rats, calves or ducks failed. One attack of fowl-pox produces immunity. In the fowl, any one of the 3 strains completely immunizes against the others. Hyperimmunization with fowl-pox virus produces in the fowl an antiserum containing viricidal antibodies. Vaccinia virus passaged in the fowl does not become converted into fowl-pox virus; it remains pathogenic for rabbits and rats. Vaccinia virus and fowl-pox virus do not show cross immunity in the hen. While fowl-pox virus easily passes through a Berkefeld filter, vaccinia virus, even after repeated passage in the hen, is still largely held back. No evidence has been obtained to show any close relationship between the virus of vaccinia and the 3 strains of fowl-pox virus investigated.