Study in Mice May Shed Light on West Nile Virus

A study in mice suggests that a flawed gene may be the reason the West Nile virus causes a life-threatening illness in some while giving others only a relatively mild infection, according to French researchers. Scientists at the Pasteur Institute in Paris reported last week in the Proceedings of the National Academy of Sciences that a strain of mice carrying a nonworking gene is quickly killed by the West Nile virus, while mice with normal genes are not.

If a similar gene variation is found in humans, it may lead to a new understanding of why only about 1 in 5 people infected with the virus develops a serious illness, the scientists said. American experts said the research is an important step toward finding a drug to treat West Nile infections.