Washington, Jul 25 (IANS): Unsure as to how a virus -- transmitted from birds to humans by blood-sucking mosquitoes -- migrated to the US and where it will strike next, researchers are now geographically tracking the strain and recording where it originates.

Several outbreaks of West Nile Virus, which causes fever or severe neurological symptoms affecting the brain, have ravaged the US since 1999.

Researchers are not certain as to how the virus migrated here - and they don't know how, or where, it will strike next.

The virus, which was first recorded in the 1930s, believed to have originated in Egypt, is now spreading globally to Western Europe and North America, says Ella Mendelson of Tel Aviv University's School of Public Health, according to the university's statement.

By examining the outbreaks and testing samples of the mosquito population from high-risk areas -- near large bodies of water, her method can identify "danger zones" and produce timely warnings of impending outbreaks, the journal Eurosurveillance reports.

And by providing more information on the dynamics and mobility of the virus, it could also solve the mystery of how the virus migrates.

Mendelson and her fellow researchers at the Central Virology Lab in Israel are geographically tracking the virus, recording where it originates, the genetic types of the virus that are circulated, and the dynamics of infection.