WASHINGTON (Reuters) - President Bush, under pressure to provide more help to Africa ahead of a Group of Eight summit next week, proposed on Thursday that Washington take on a greater role in combating malaria in sub-Saharan Africa as part of what he called a doubling of U.S. aid. With Africa a top agenda item for G8 leaders meeting July 6 to 8 in Gleneagles, Scotland, Bush said he would ask Congress to spend $1.2 billion through 2008 to help fight malaria, which claims an estimated 1.2 million people a year worldwide, 95 percent of them in sub-Saharan Africa. In...