Some immunological aspects of a recent Australian isolate of infectious bronchitis virus

An infectious bronchitis virus, designated G48, isolated from birds during an outbreak of nephritis in a previously vaccinated broiler flock, overcame the resistance induced in birds vaccinated with 2 commercially available vaccines. Birds vaccinated with the A isolate of infectious bronchitis resisted challenge with this new virus. Cross neutralisation studies revealed that the new virus was serologically distinct from the 4 viruses tested. Homologous antiserum to G48 did not neutralise the other viruses and only antiserum to the A virus completely neutralised the new virus.