The Bill and Melinda Gates Foundation announced a $30 million grant yesterday to help fund a study on whether successfully treating genital herpes can help reduce HIV transmission. The grant to the University of Washington School of Medicine will help finance research at 10 sites in Africa, India and Latin America. The study will seek to determine whether the generic drug acyclovir, widely used to treat genital herpes, can reduce HIV transmission rates. At least half of the HIV-infected people worldwide are also infected with herpes simplex virus type 2, or genital herpes. Through sores, they "appear to be significantly more likely to transmit HIV than other HIV-infected people," the foundation said. People with genital herpes are also about twice as likely as others to become HIV-infected if exposed to the virus.