‘Shocking’ genetic data suggests Ebola hid in survivor for 5-6 years

The Ebola viruses causing a new epidemic in Guinea are surprisingly similar to the viruses identified during the massive outbreak in West Africa that lasted from 2013 to 2016, according to a new genetic analysis. The discovery suggests that the virus may have silently persisted in a survivor for at least five years and that the current outbreak was started by that unlucky person, rather than an overflow from an animal reservoir.

In the genetic analysis posted online Friday, a group of international researchers report that the Ebola viruses collected during the current epidemic in Guinea show only a dozen genetic differences compared to the Ebola variants collected in the same region. from Guinea in 2014. Based on what researchers know about the rate at which Ebola collects these genetic substitutions – its rate of evolution – this number of accumulated differences should have totaled more than 110 during this period, not 12.

“This number of substitutions is much lower than one would expect during sustained human-to-human transmission,” the researchers write in their analysis. Instead, they note that such a slow rate of progression is a “hallmark of persistent infections.”

“Therefore, the index case from the Guinea 2021 cluster was likely infected from a persistent source, such as through sexual transmission from a [Ebola] survivor, ”they conclude.

The Ebola virus is known to persist in some survivors, especially in places where there may be a weak immune system, such as the testes or eyeballs. A 2016 study reported a resurgence of the virus in the seminal fluid of a survivor more than 500 days after the initial infection.

Yet the period of more than five years was “shockingTo many virologists and public health experts. And it raises various concerns for the many survivors of past outbreaks, some of whom may have had mild cases of Ebola without realizing it. In particular, many people known to have survived Ebola face stigma, and the possibility of persistence for several years is likely to amplify this problem.

During the 2013-2016 epidemic in West Africa, more than 28,000 people were infected with the virus and more than 11,000 died. It is the largest Ebola outbreak in history. Most of the cases and deaths have been in Guinea, Liberia and Sierra Leone. The outbreak began with a reported case in an 18-month-old boy in December 2013; the boy is believed to have caught the bat virus.

The current outbreak, which was declared on February 14, has sickened at least 18 and killed nine. Vaccination efforts are currently underway to stop the spread of the virus.