Men who recover from the Ebola virus should avoid having sex for three months to minimize the risk of transmitting the virus on in their semen, the World Health Organization (WHO) said Friday via Twitter.

WHO also gave a fuller statement on its website, saying that while the sexual transmission of Ebola has not been documented, studies have found that the live virus can remain in semen for up to 82 days after the onset of symptoms.

“Because of the potential to transmit the virus sexually during this time, they should maintain good personal hygiene after masturbation, and either abstain from sex (including oral sex) for three months after onset of symptoms, or use condoms if abstinence is not possible,” according to the statement.

Ebola has infected nearly 16,000 people in the current outbreak, with Guinea, Sierra Leone and Liberia seeing the most cases. The virus normally spreads via bodily fluids such as blood and saliva.

Write to Naina Bajekal at naina.bajekal@time.com.