Epidemiology of influenza during 1957--75 in the Union of Soviet Socialist Republics and the German Democratic Republic.

Analysis of clinical data collected by the epidemiological services in both countries showed that each shift or drift in the antigenic structure of the influenza virus resulted in epidemics in both countries. Depending on the degree of antigenic change, both shifts and drifts influenced the speed of epidemic spread and the time of occurrence and the intensity of the epidemics. However, the analyses did not reveal a direct relation between degree of antigenic variation and the attack rate or the severity of the epidemic.

Serological relationships between certain avian and animal paramyxoviruses.

An avian paramyxovirus designated Robin/Hiddensee/19/75 proved to be related to the Yucaipa virus group in cross haemagglutination inhibition test (HIT). Whereas the prototype parainfluenza viruses did not react with the antiserum raised against the Robin virus, a newly isolated bovine parainfluenza 3 virus was shown to be inhibited up to half the homologous titre. Possible antigenic relationships between avian, mammalian and human paramyxoviruses are discussed.