A growing volume of data from careful clinical observation and testing of people who have recovered from acute Ebola virus disease indicates that the Ebola virus can persist at various sites in the body for many months in some people. Such sites include the inside of the eye, semen, amniotic fluid, the placenta, breast milk and the central nervous system.
A preliminary study on Ebola virus persistence in the semen of male survivors in Sierra Leone, has found that some men still produce semen that test positive on real time – polymerase chain reaction (RT-PCR), a test used to detect Ebola virus genetic material (RNA) – for nine months or longer.
All of the men who were tested in the first three months after their illness began were positive. More than half of men who were tested between four to six months after their illness began were positive, while one quarter of those tested between seven to nine months after their illness began also tested positive.
While it is now clear that virus persists longer in semen than previously thought, the risk of people being infected with Ebola by those who have survived the disease is probably low. Although sexual transmission by survivors with persistent virus is a possibility, it appears to be rare.