An Ebola outbreak in Guinea that has so far sickened at least 18 people and killed nine has stirred difficult memories of the devastating epidemic that struck the West African country between 2013 and 2016, along with neighboring Liberia and Sierra Leone, leaving more than 11,000 people dead.
But it may not just be the trauma that has persisted. The virus causing the new outbreak barely differs from the strain seen 5 to 6 years ago, genomic analyses by three independent research groups have shown, suggesting the virus lay dormant in a survivor of the epidemic all that time. “This is pretty shocking,” says virologist Angela Rasmussen of Georgetown University. “Ebolaviruses aren’t herpesviruses”—which are known to cause long-lasting infections—“and generally RNA viruses don’t just hang around not replicating at all.”
Scientists knew the Ebola virus can persist for a long time in the human body; a resurgence in Guinea in 2016 originated from a survivor who shed the virus in his semen more than 500 days after his infection and infected a partner through sexual intercourse. “But to have a new outbreak start from latent infection 5 years after the end of an epidemic is scary and new,” says Eric Delaporte, an infectious disease physician at the University of Montpellier who has studied Ebola survivors and is a member of one of the three teams. Outbreaks ignited by Ebola survivors are still very rare, Delaporte says, but the finding raises tricky questions about how to prevent them without further stigmatizing Ebola survivors.