Characterisation of influenza viruses isolated from turkeys in Great Britain during 1963--1977.

Seven influenza viruses isolated from turkeys in Great Britain since 1963 were typed by haemagglutination inhibition and neuraminidase inhibition tests as: A/turkey/England/63 (Hav 1 Nav 3), A/turkey/England/66 (Hav 6 N2), A/turkey/England/69 (Hav 7 N2), A/turkey/Scotland/70 (Hav ? Neq 1), A/turkey/England/N28/73 (Hav 5 N2), A/turkey/England/110/77 (Hav 6 N2), A/turkey/England/647/77 /Hav 1 Neq 1). A/turkey/Scotland/70 failed to show a haemagglutinin relationship with any of the representative strains and may possess a hitherto unreported haemagglutinin subtype. Intravenous pathogenicity tests in six-week-old birds showed only A/turkey/England/63 to have high virulence for turkeys and chickens. A/turkey/England/69 produced some signs of disease in chickens and, to a lesser extent, turkeys but all other isolates were avirulent.