BERKELEY, California: Researchers in California report they have developed a new chemical compound that could one day treat flu infections by blocking an enzyme, called neuramindase, that the virus needs in order to reproduce. Early tests of the experimental GS 4104 compound have produced better-than-expected results by knocking out samples of all major flu types in five different species of lab animals, according to a report in the latest issue of the Journal of the American Chemical Society. GS 4104 contains the infection by preventing newly-formed viruses from leaving the host cell. But don't expect to be able to take a pill to get rid of the flu anytime soon. Human trials are planned for later this year, with results expected in two or three years at the earliest. Even if those trials are successful, the main use of an anti-flu pill will probably be preventative. Although you can be sick for several weeks fighting off the effects of the flu, the virus itself only exists in the body for up to the first six days, meaning that you would have to take the pill in the earliest stages of infection to prevent the virus from spreading.