Further studies on the classification of fowl adenoviruses.

In addition to the 8 fowl adenovirus serotypes described previously, 3 new serotypes were recognized. Two, A-2 and C2-B, were isolated in the U.S.A., and one, 380, in Northern Ireland. In addition another isolate, X-11, has a broader antigenicity than YR-36 and therefore should be used instead of YR-36 as prototype strain. It is concluded that there are at least 11 distinct fowl adenovirus serotypes on the basis of the serum-neutralization test.