When flu takes wing
In spite of the fact that it is now about 30 years since the human influenza virus was isolated in the laboratory, long-term prediction of influenza epidemics is not possible. However, recent epidemiological studies with human and animal influenza viruses may ultimately improve our ability to predict the future behaviour of the influenza virus in man. We now know that influenza A viruses containing a ribonucleoprotein antigen identical to that of human influenza A viruses can be isolated from outbreaks of respiratory illness in swine, horses and domestic and wild birds. These findings led Dr P. P. Laidlaw in 1935 to suggest that a virus antigenically closely related to the swine influenza virus may have been responsible for the 1918 pandemic of influenza (so-called Spanish Influenza). A fresh approach to the problem of antigenic relationships between human and animal influenza A viruses has been made by Drs H. G. Pereira, W. G. Webster and B. Tumova at the National Institute for Medical Research, London. They examined the antigenic structure of an influenza virus recovered from turkey flocks in the USA in 1965, and found that the virus contained a haemagglutinin antigenically distinct from that of human influenza viruses, while its neuraminidase appeared to be identical with that found in human A2 virus strains. These findings suggest that the turkey virus may have arisen as a result of the genetic interaction of an avian and a human influenza virus. Perhaps this is the reason why most influenza epidemics appear to originate in China, with its vast populations of people following agricultural pursuits.
From ¿ìè¶ÌÊÓƵ, 23 January 1969
Advertisement
