Adenoviruses of chickens: serologic groups

By literature review and experimental studies, 57 adenovirus isolants from chickens were grouped into 10 distinct serotypes. In plaque-reduction tests, 20 antibody units were reacted with 32-320 plaque-forming units of virus. Viruses that were neutralized (80% or greater reduction in titer) by a given serum were considered to belong to that serotype. Used to distinguish among serotypes were their antisera. One-way neutralization occurred in only two instances; in both cases it was traced to contamination of the virus inocula used to induce specific antiserum. Recloning corrected the problem. Of the 10 serotypes described, all are known to exist in the United States, 7 were found in Northern Ireland, and at least 6 have been shown to occur in Japan.