Preliminary results of a study into persistence of Ebola virus in body fluids show that some men still produce semen samples that test positive for Ebola virus nine months after onset of symptoms. The report, published today in the New England Journal of Medicine, provides the first results of a long-term study being jointly conducted by the Sierra Leone Ministry of Health and Sanitation, Sierra Leone Ministry of Defence, the World Health Organization and the U.S. Centers for Disease Control and Prevention.