Ebola Virus RNA May Persist in Semen, Breast Milk for Longer Than Anticipated

Ebola virus
Ebola virus
Data from a large sample of Ebola survivors confirmed the persistence of Ebola viral RNA in semen for up to 6 months.

Data from a large sample of Ebola survivors confirmed the persistence of Ebola viral RNA in semen for up to 6 months, according to the results of a study published in Open Forum Infectious Diseases. More importantly, the study was the first to report Ebola virus RNA detection in the breast milk of a woman 1 month after delivery who became pregnant 7 months after having recovered from the disease.

In this prospective, multicenter, open cohort study (known as PostEbogui), patients were recruited after they were discharged from an Ebola treatment unit at 4 different sites in Guinea between March 2015 and July 2016. Body fluids, which provide the major route of human-to-human transmission of the virus, were collected from patients and assessed for viral RNA at inclusion, 1 and 3 months afterward, and subsequently every 6 months for up to 40 months.  

Each laboratory used their specific polymerase chain reaction (PCR) methods, and depending on availability of assays and laboratories where tests were performed, the following quantitative reverse-transcription PCR (qRT-PCR) assays were used: RealStar® Filovirus Screen RT-PCR Kit 1.0 (Altona Diagnostics, Germany), an in-house nucleoprotein qRT-PCR assay, and the Xpert® Ebola Assay (Cepheid AB, Sweden).

Of the 360 male survivors, 277 (77%) donated a semen sample at least once. The median time between discharge from treatment unit and semen donation was 14.4 months for the first sample and 41.7 months for last sample. A total of 1777 PCR tests were conducted on 1368 samples (mean 4.9 samples/patient): 620 samples using RealStar Filovirus Screen RT-PCR, 531 samples using in-house nucleoprotein qRT-PCR assay, and 626 samples using Xpert Ebola.

Of the 277 men who donated a semen sample, 27 (9.8%) tested positive for Ebola viral RNA in at least 1 semen sample. The probability of remaining positive for Ebola viral RNA in semen was estimated at 93.02% and 60.12% after 3 and 6 months, respectively. The downward trend continued to 0.96% after 18 months and 0.06% after 24 months.

Samples of other body fluids were also evaluated, including breast milk, saliva, cervicovaginal secretions, feces, and urine (N=4050). Two salivary samples demonstrated Ebola viral RNA at days 5 and 34 after discharge from an Ebola treatment unit; 3 urine samples were positive at days 7, 43, and 55 after discharge. One breast milk sample was positive at day 58; however, on subsequent testing of 54 samples not previous evaluated, results showed 1 sample that was positive 500 days after discharge.

Researchers observed a positive and significant relationship between older age and the period of viral RNA detection in semen (r = 0.51; P =.0065). Multivariate analysis showed that eye pain and joint pain were significantly associated with RNA detection in semen (P =.036 and .047, respectively).

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In addition, the higher antibody levels in patients with positive viral RNA results were significantly different for glycoprotein (P =.05), for viral protein-40 (P =.05), and especially for nucleoprotein (P =.001).

Although semen appears to be the body fluid at highest risk for additional transmissions after discharge, “more studies are needed on pregnant women, including when pregnancy occurred after discharge from an [Ebola treatment unit], to evaluate whether pregnancy can have an impact on relapse of [Ebola virus disease] and to educate healthcare workers on this potential risk,” concluded the researchers.


Keita AK, Vidal N, Toure A, et al; PostEbogui Study Group. A 40-month follow-up of Ebola virus disease survivors in Guinea (PostEbogui) reveals long-term detection of Ebola viral ribonucleic acid in semen and breast milk. Open Forum Infect Dis. 2019;6(12):ofz482.