The presence of avian adenoviruses and adeno-associated viruses in healthy chickens.

Avian adenoviruses were isolated from 56 of 106 fecal and rectal tissue samples taken from apparently healthy young chickens on 4 farms. Only one isolation was made from the 37 samples from 3- and 4-week-old chicks, while the isolation frequency was 64-100% in groups 5 weeks old and older. The 56 adenovirus isolates were classified into 6 serotypes. Vurses of 3 or 4 types were found on each farm. Avian adeno-associated virus CF antigens were found, using chicken embryos coinfected with an adenovirus helper, in 2 of the 38 adenovirus isolated studied.