Reuters: Economic crisis and climate change concerns could affect the fight against the AIDS virus and lead to a "universal nightmare," the head of the United Nations’ agency for HIV/AIDS said on Sunday. The global economic downturn has brought about greater inequality and could increase vulnerability and fuel the epidemic, said Michele Sidibe, executive director of UNAIDS. About 33.4 million people worldwide are infected with HIV and the AIDS virus. Since AIDS emerged in the 1980s, …