Because Marburg and Ebola viruses can persist in semen and be sexually transmitted, the World Health Organization (WHO) recommends that patients who have had either infection and their sex partners should abstain from all types of sex or use condoms correctly and consistently until one of the following occurs: Until 2 tests for the virus are negative If testing is unavailable, until ≥ 12 months have passed since symptom onset For more information, see the WHO: Interim recommendations for infection prevention and control, WHO: Marburg virus disease, and WHO: Interim advice on the sexual transmission of the Ebola virus disease.