The CDC has warned the public that the Ebola virus may survive in semen long after it is undetectable in other bodily fluids: 

They have recommended that men who survive Ebola use condoms indefinitely after recovery until we learn more. The scientific community still unsure how transmission works through semen.

CDC announced the warning after a Liberian woman contracted Ebola. It appears to have happened after sex with a man who had recovered from Ebola. Tests of the man’s semen revealed the presence of the virus five months after his recovery. 

Before this, transmission was previously thought highly unlikely after this time period.

CDC issued a warning document that says:

 "Men, to protect your partner, don’t have sex (oral, vaginal, or anal) with anyone until we know more.” 

"If you do have sex, use a condom the right way every time. There is a small risk of spreading Ebola if you use condoms.” 

The document also notes that the virus can survive in breast milk after symptoms have passed. Although Ebola was known to persist in semen longer than other bodily fluids, it was previously thought that three months was a long enough to prevent transmission.

According to reports, the infected woman had no other known potential sources of transmission. Genetic sequencing of the virus that infected her showed mutations that matched those from the man's semen, while being different from other recent cases.

The bad news is this has raised new possibilities for further outbreaks and may encourage stigmatization of Ebola survivors.

The good news is the only new case of Ebola recorded in Liberia since mid-February. New cases in Sierra Leone and Guinea are running at a rate of between 30 and 40 a week, less than a tenth of the rate at the peak of the epidemic.