MADISON, Wisc. -- Studying a descendant of the 1918 influenza virus that killed at least 20 million people worldwide, University of Wisconsin-Madison virologists discovered a new molecular trick some viruses use to transform from dangerous to deadly.

In research detailed in the Aug. 18 Proceedings of the National Academy of Sciences, UW-Madison virologists Hideo Goto and Yoshihiro Kawaoka have found a molecular mechanism that allows influenza viruses to cause sweeping damage throughout the body. Influenza infection is normally limited to respiratory systems, but this previously undetected process gives the virus the deadly ability to attack many organs in the body.

"This finding provides an additional marker for scientists to be aware of in their surveys of emerging viruses," said Kawaoka. "This could be another important indicator of whether a virus is dangerous and potentially lethal."

Kawaoka said the extreme virulence of the 1918 influenza virus is a public health mystery. One of the worst infectious disease outbreaks in human history, the 1918 flu killed not only vulnerable populations such as the elderly and young children, but an unusually high number of otherwise healthy young adults.

While this finding offers no definitive explanation for the 1918 virus, Kawaoka said it is a question that warrants further scientific study.

Kawaoka and Goto, researchers in the UW-Madison School of Veterinary Medicine, studied a virus closely related to the 1918 strain which appeared nearly a decade later in humans. The virus is widely studied for its ability to replicate in the brains of mice, but Kawaoka also found it could replicate in a number of different organs.

Their discovery concerns proteins on the virus' surface that allow the virus to attach to target cells. Normally, a viral surface protein called hemagglutinin must be chopped into two parts before the virus can infe
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Contact: Yoshihiro Kawaoka
kawaokay@svm.vetmed.wisc.edu
(608) 265-4925
University of Wisconsin-Madison
17-Aug-1998