We’ve reported some good news about Ebola, after no new cases were reported for over a month, but the struggle is not over. New study detailed how Ebola can survive in the semen of male survivors for months, potentially triggering new outbreaks.

Ebola virus is still detectable in the seminal fluid of a quarter of survivors up to 9 months after infection. Image credits: CULTURA RM/ALAMY

Scientists have known that traces of Ebola can remain in the blood since 1999, but two papers published in The New England Journal of Medicine today offer more detail about how this happens and how it could rekindle a new outbreak. The studies was separate, but the main conclusion was the same: male survivors of Ebola should pay extra attention and always use contraception.

The first study focused of nearly 100 men in Sierra Leone who survived the dreaded viral illness, and researchers found traces of Ebola in the semen of half of them. It seems that the chance of having this onset is biggest immediately after the disease has been defeated and decreases in time. All 9 men who were tested 2-3 months after they fell ill had Ebola RNA in their semen, compared to only 26 out of 40 men infected 4-6 months earlier and 11 of 43 for infections 7-9 months earlier.

In the other study, researchers from Liberia and the United States present the best evidence yet of sexual transmission. This complements the other findings and shows that not only does Ebola survive after it is thought cured, but it can also be sexually transmitted. With huge numbers of survivors existing in Western Africa, a re-emergence of the disease could be devastating. The World Health Organization said sexual transmission was “rare”.

Margaret Chan, the director general of the WHO said we still don’t properly understand what existing Ebola treatments do.

“Does it mean they are still infectious or are they just fragments? We don’t have the definitive evidence yet. The degree of uncertainty is worrying, that’s why we need to take precautionary measures, so we advise survivors to take protection through contraception.”

Also, Prof David Heymann, from the London School of Hygiene and Tropical Medicine, underlined the necessity of using condoms to stay safe.

“Condoms should be used as a precautionary measure until better understanding is gained through long-term study. This must be done in a way that prevents discrimination, and sociologists must work with health promotion teams and community leaders, as well as survivor groups, so that language is understandable and not offensive. Past outbreaks have not been reignited by survivors, but numbers have been small, and no sexual transmission was recorded prior to the current outbreaks.”

These studies come right after a British nurse who was apparently cured of Ebola earlier this year is now in a critical condition. Doctors have said she is suffering an “unusual late complication” and were baffled by her deteriorating condition.

It seems like we still have a way to go before we can safely say the Ebola outbreak is over.