Scientists stumbled upon estrogen as a potential weapon against Ebola while looking to find new uses for old drugs. Researchers at the U.S. Army Medical Research Institute of Infectious Diseases in Maryland and at the University of Virginia in Charlottesville screened 2,000 existing drugs, in search for chemical compounds that were effective against Ebola. It was discovered that a number of human-made drugs, including selective estrogen receptor modulators, or SERMS, blocked Ebola's entry into cells in lab cultures and in mice.