Ebola: New Concerns about Sexual Transmission

Ebola virus appears to persist in survivors longer than thought, leading the US Centers for Disease Control and the World Health Organization to urge men who survive infection to use condoms indefinitely. The public health fear is that sexual transmission from survivors could lead to a new outbreak of cases.

The US Centers for Disease Control and Prevention (CDC) is urging male Ebola survivors and their sex partners to continue to use condoms indefinitely—not just for the 90-day period it has been recommending.

“Ebola virus can persist in the seminal fluid of convalescent men for longer than previously recognized and can potentially lead to sexual transmission of Ebola,” the CDC said.

The policy change comes after a case in which an Ebola survivor in Liberia is strongly suspected of having given the virus to a woman through sexual contact that happened 199 days after he came down with the virus.

The public health fear is that if the virus survives in patients for long periods after they have recovered, and is sexually transmitted, there could be a second wave of infections in populations where Ebola had been considered under control.

The researchers believe that since a partial genome sequence of viral RNA from the man matches a similar sequence from the woman, she was infected by having sex with him. The man has several close relatives who died from Ebola though his own case was not severe.

They are doing further tests on his semen sample to amplify existing Ebola virus RNA and complete a genomic sequencing.

His clinical records and the fact that he has several close relatives who died from confirmed Ebola infection suggest that he had Ebola in early September 2014, the CDC said. Tests done while he was being treated were inconclusive.However, after the woman was infected and named him as a possible source of the virus, he was retested. Ebola virus RNA was found in the man’s semen in March 2015. That does not prove the presence of infectious virus—but the female patient who had sex with him had no other known exposure to the virus. Thinking she could have contracted it elsewhere in the community, researchers compared the genetic signature in her sequenced viral RNA and found it differed from that in the last known cluster of community acquired cases.

That makes it unlikely that she was infected from unrecognized, ongoing community outbreak transmission, the CDC said.

“Until more information is known, contact with semen from a male survivor should be avoided,” and condoms should be used for all sexual encounters, the CDC cautioned today in an alert in this week’s Morbidity and Mortality Weekly Report.

The World Health Organization and other organizations fighting Ebola in West Africa issued similar guidelines. The organizations also noted they should try to find a way to spread that advice without unnecessarily stigmatizing Ebola survivors.

The CDC said it plans additional studies to learn how long the virus persists in women who survive Ebola infection.