Never underestimate Ebola’s ability to surprise, even when the virus goes quiet.
This week, the World Health Organization announced that, for the first time, West Africa has gone two weeks without reporting any new cases.
But this cautiously optimistic news comes on the heels of an alarming development: Pauline Cafferkey, a Scottish nurse who survived an Ebola infection, is back in the hospital fighting for her life. The virus has somehow staged a second attack — more than eight months after Cafferkey was declared Ebola free.
This week also saw the publication of two papers in the New England Journal of Medicine, both of which underscore Ebola’s stubborn ability to linger in the semen of survivors. One study tested 93 Sierra Leoneans at different stages of recovery and found that nearly half had detectable virus in their semen; in one case, nine months after the man was first infected.
Infectious disease experts emphasize that Cafferkey’s risk to the public is extremely low. They also believe that sexual transmission of Ebola from survivors is rare, though the second NEJM study found evidence that this likely caused the infection of a Liberian woman in March.
In the ongoing saga that is West Africa’s Ebola epidemic, the virus has thrown up surprises at every turn. Even as the outbreak wanes, its unprecedented 17,000 survivors are presenting new mysteries to doctors and scientists.
“We wanted to take the opportunity of this big epidemic to better understand the dynamics of this virus,” said WHO epidemiologist Dr. Nathalie Broutet, who co-authored one of the NEJM papers.
“It’s the first time that we can really document in a large number of people, of survivors, that there’s Ebola virus in the semen after recovery.”
This epidemic has proven that Ebola’s physical consequences can persist long after a patient is discharged from hospital. About half of survivors suffer from joint pain, for example — sometimes so debilitating they can’t work or carry out daily activities.
Even after a patient has recovered, the virus can continue hiding in “immune-privileged” sites on the body, said Dr. Armand Sprecher, an Ebola expert with Médecins Sans Frontières.
These sites are usually important organs — the eye or brain, for example — that have special barriers, which protect them from being attacked by the body’s own immune system when it responds to a foreign invader.
“This is a destructive process (and it) is limited in some parts of the body where the destruction could be counterproductive,” Sprecher said.
The flip side is that these sites are also perfect hiding spots for wily viruses like Ebola. Sprecher suspects one reason the virus has silently persisted in certain patients is because of new drugs introduced during this outbreak.
Because Ebola kills swiftly, “one of the things (a drug) will do is lengthen your course of illness,” he said. “And if it does that, the virus that would have never gotten to your brain — because it would’ve killed you before it got there — has a longer pathway and reaches into tissues that it might not have reached.”
More studies are now underway to better understand Ebola’s hidden reservoirs in the body and Broutet plans to analyze other bodily fluids taken from male and female survivors, including vaginal secretions, tears and urine.
What’s already clear, however, is the importance of staying alert for Ebola — even after patients have recovered.
But Sprecher also warns against overreacting to new information coming to light and further stigmatizing survivors.
“(If we) create an environment where people will hide the fact that they’re a survivor, or hide the fact that they’re ill, that will defeat the very surveillance system we’re setting up to defeat this outbreak,” he said.