a1 Virus Reference Laboratory, Central Public Health Laboratory, Colindale Avenue, London, N. W. 9
The identification of 18 strains of haemadsorbing viruses as parainfluenza type 4 viruses subtypes A and B is reported, as is a serological survey to show the distribution of antibody to these viruses in various age groups. The results suggest that although isolation of the virus is infrequent, infection in early childhood is common and the viruses may be important respiratory pathogens.
I wish to thank Dr G. B. Bruce White for kindly providing sera and also Dr B. E. Andrews, Dr Suzanne K. R. Clarke, Dr F. O. MacCallum, Dr E. M. Mackay Scollay, Dr Hélène J. Mair and Dr J. O'H. Tobin for sending the strains.
(Received March 06 1969)