A new, preliminary genetic analysis suggests that the current Ebola outbreak in Guinea may have originated with a survivor of the 2014-2016 West African Ebola outbreak, rather than from an animal-to-human transmission.
According to the pre-print report, the outbreak likely started with the survivor infecting a sexual partner with the deadly virus through semen — after the virus lay dormant in the man for at least 5 years.
The analysis, posted online Friday, was conducted by scientists from Guinea, the Institut Pasteur in Senegal, the University of Nebraska Medical Center, the University of Edinburgh, and the company PraesensBio.
According to the Infectious Diseases Society of America (IDSA), the longest an Ebola survivor was believed to have shed the virus was about 500 days.
The previous Ebola outbreak resulted in 28,000 cases and 11,000 deaths, mainly in Guinea, Liberia, and Sierra Leone, according to the new report. The current outbreak in Guinea has resulted in 18 cases and has killed nine people, according to The New York Times.
The news is “sobering,” said William Schaffner, MD, a communicable disease epidemiologist and pandemic preparedness expert at Vanderbilt University in Nashville.
“Who would have thought that the Ebola virus could remain latent in a person — a male — for 5 years and then set off another outbreak?” Schaffner said. “Until this news came in, I think we all thought this latest Ebola outbreak was a consequence of an introduction from an animal species.”
“This gives a whole new public health resonance to the notion that male Ebola survivors are a potential reservoir of this infection for many years,” he said.
Schaffner said that the testes, in addition to the eye and the central nervous system, are locations in the body where the Ebola virus is known to hide.
The new report raises the question, he said, about whether some of the past outbreaks in Africa weren’t introduced from the wild but instead occurred because a survivor initiated the infection in a partner.
The particular danger of the virus lying dormant in the testes, rather than the eye or in the nervous system, is that it could be transmitted to someone sexually, Schaffner said.
The findings in the genetic analysis could exacerbate the stigma for survivors, he said.
It also raises the question about whether widespread vaccinations are needed in equatorial Africa, he said.
Additionally, even though Ebola vaccines are very effective, he said, it isn’t known how long they could protect people.
Another public health measure may be promoting more condom use, he said, which comes with its own set of difficulties.
In light of this latest news, male survivors will move into the research spotlight, Schaffner said, and volunteers will be asked to provide semen specimens to find out whether this is a one-time event or something that happens commonly.
Michael Ryan, MD, executive director of the World Health Organization (WHO) Health Emergencies Programme, said in a briefing on Friday that the WHO has sent more than 30,000 vaccine doses to the country.