RELATIONSHIPS OF INFLUENZA-A VIRUSES WITH AVIAN SUBTYPE-1 HEMAGGLUTININ INCLUDING THE FOWL PLAGUE VIRUSES

Seven influenza A viruses with avian subtype 1 hemagglutinin (Hav1) were compared on the basis of neutralization in embryonated chicken eggs, hemagglutination-inhibition, neuraminidase-inhibition, and plaque size determination in a MVPK-1 cell line. One virus, influenza A/turkey/Oregon/71 was avirulent, whereas the other six isolates were virulent for avian species. The seven viruses were placed into four groups based on the above criteria: Group 1. Influenza A/FPV/Dutch/27, A/FPV/Brescia/02, and A/FPV/Steele/59; Group 2. A/FPV/Rostock/34, and A/FPV/Alexandria/45; Group 3. A/turkey/England/63; and Group 4. A/turkey/Oregon/71. The similarities and dissimilarities provide information as to the antigenic spectrum of the viruses that will be of importance in future vaccination studies. © 1979.