Genetic susceptibility to West Nile virus 22:00 19 August 02 NewScientist.com news service A genetic mutation might explain why only one fifth of people infected with West Nile virus go on to develop symptoms - and why only one fifth of these people develop a severe, often fatal, brain inflammation, say French researchers. West Nile virus, named after the area in Uganda where it was first detected, is mosquito-borne. It belongs to the family of flaviviruses, which includes dengue and yellow fever. And it is currently sweeping across the US, with the first recorded infection on the west coast reported...