The Ebola virus can linger in the semen of men who have recovered from the deadly illness much longer than previously thought, according to a new study.
Previous studies found evidence of the virus in male semen up to 90 days after recovery. But in the case of one man in Liberia who was screened for the presence of Ebola, viral fragments were found in his semen 565 days after he had recovered from the illness.
The Men’s Health Screening Program in Liberia, with support from the World Health Organization and the U.S. Centers for Disease Control and Prevention, is conducting surveillance in the wake of the Ebola epidemic. Male Ebola survivors may voluntarily be tested monthly. They receive condoms and counseling on safe sex practices.
In the latest study, the program screened 429 male survivors. Researchers found that 38 of the men, or 9 percent, had viral DNA fragments in their semen a year after recovery. Evidence of the virus seemed to persist the longest in men over 40. Researchers said they were concerned that their finding could be a low estimate.
It’s not known at this point whether any such men could still transmit Ebola through sexual intercourse, since the DNA test can’t determine whether the virus is active.
The results of the screening were published in the journal Lancet Global Health. The study was based on an analysis of data collected between July 2015 and May of this year.
The director of the CDC, Thomas Friedman, was quoted as saying Liberia’s surveillance program “provides important insights into how long Ebola remains in semen, a key component to preventing flare-ups of the disease and protecting survivors and their loved ones.”
In light of the uncertainty, news that Ebola persists in semen alarmed public health officials, potentially posing a new challenge following the epidemic that killed more than 11,000 people in West Africa over a period of more than two years ending in March 2016.