Virulence of 1918 flu virus studied

ATLANTA, Oct. 2 (UPI) -- U.S. scientists have completed the first comprehensive analysis of an animal's immune response to the 1918 influenza virus.

The researchers, led by Michael Katze of the University of Washington's School of Medicine, say they found the 1918 virus triggers a hyperactive immune response that may contribute to the lethality of the virus. Furthermore, their results suggest it is the combination of all eight of the 1918 flu virus genes interacting synergistically that accounts for the exceptional virulence of the virus.

The work with the fully reconstructed 1918 virus was conducted by co-author Terrence Tumpey in a biosafety level 3-enhanced laboratory at the U.S. Centers for Disease Control and Prevention in Atlanta.

"This elegant research gives a detailed picture of the overzealous host reaction to infection by a fully reconstructed 1918 influenza virus," said National Institute of Allergy and Infectious Diseases Director Anthony Fauci. "The research provides clues as to why the flu of 1918 was so deadly, and may also help us better understand the disease process that occurs when people are infected by emerging avian influenza viruses, such as the H5N1 strain."

The study appears online in the journal Nature.