Serological relationships within the group E fowl adenoviruses.

Antisera were raised in chickens to six group E fowl adenoviruses (FAV) which have been divided into a highly virulent (hypervirulent) and a mildly virulent subgroup using restriction endonuclease analysis. Virus neutralisations showed that these two distinct restriction endonuclease groups were distinguishable serologically, and indicated a possible vaccine candidate for use against the hypervirulent FAV. The suitability of this candidate was established in challenge experiments where vaccination with this virus protected against challenge from another hypervirulent virus as well as one of the mildly virulent FAV.