Sunlight may make a dormant AIDS virus start to reproduce itself by activating a genetic trigger, scientists reported Thursday.

The results of new test-tube experiments do not necessarily mean people infected with the AIDS virus should stay out of the sun, scientists stressed.But "I certainly wouldn't tell somebody who had the virus or is seropositive (possibly infected) to go sit in one of these ultraviolet (tanning) spas," said Martin Rosenberg of Smith Kline & French Laboratories.

Rosenberg and Smith Kline colleagues from King of Prussia, Pa., and Belgium report their work in the British journal Nature.

They found that the virus grew faster in cells that had been exposed to ultraviolet light, a component of sunlight, and that exposing infected cells to ultraviolet light or sunlight activated a genetic trigger that controls virus reproduction.