a1 C.S.I.R. and U.C.T. Virus Research Unit, University of Cape Town, South Africa
The aetiological agent of an epizootic among Common Terns (Sterna hirundo) in South Africa in 1961 was isolated from several sick birds and named Tern virus. It was classified on the basis of antigenic and morphological properties as a strain of avian influenza virus, Myxovirus influenzae A/Tern/South Africa/1961. The strain-specific antigen of Tern virus was unrelated to all known influenza strains with the single exception of Chicken/Scotland/1959 virus and the two viruses may be regarded as variants of the same strain. This relationship raised the interesting epidemiological possibility of the spread of infection between sea-birds and domestic poultry because the Common Tern migrates between Europe and South Africa.
(Received December 31 1965)