Since the Ebola virus was first identified in 1976, doctors have approached the disease with a reasonable idea of what those infected were facing. The disease was known to be grim – a hemorrhagic fever which caused copious amounts of bleeding and, in up to 90 percent of cases, death – but those who survived the acute infection could and did fully recover from the virus. At least, that’s what we thought until now.
When Scottish nurse Pauline Cafferkey was admitted back into the infectious diseases unit of the Royal Free hospital in London on October 9th, nine months after being declared Ebola-free, and then became critically ill, all the previous assumptions about the long-term effects of this virus went out the window. Initially, doctors at the London hospital attributed her condition to an “unusual late complication” of Ebola. But this week, with Cafferkey fighting for her life, doctors determined that the source of her illness was no longer just a complication, but that she was actually suffering from a recurrence of Ebola.
The case has stunned even the most seasoned Ebola experts, with leading scientists describing Cafferkey’s situation as “staggering” and “unprecedented.” While previous studies have shown that the Ebola virus can linger in certain bodily fluids for weeks or months after a patient has recovered, this is the first case of Ebola recurrence ever documented in the scientific literature.
“This is totally unprecedented. We’ve never seen this, and there’s so much uncertainty,” Jeremy Farrar, a specialist in infectious diseases and director of the Wellcome Trust, told Reuters. “Is this a one off? A very rare event? Or is this going to be quite common? The honest answer is we don’t know.”
Cafferkey’s relapse, along with uncertainty about her prognosis and what it may mean for thousands of other Ebola survivors, serves as a reminder of how little is known about the virus that ripped through Western Africa claiming more than 10,000 lives. For one thing, it is not immediately clear why Cafferkey is again grappling with an active Ebola infection so many months after appearing to have beaten it, as thousands of others have in Africa, along with a handful in the U.S., and Europe. “Speculation has focused on the potential role of Ms. Cafferkey’s severe initial illness, and even on the experimental treatments she and the few other patients treated in Western hospitals received,” the New York Times reports.
But it’s also quite possible (likely, even) that Cafferkey is not the first Ebola survivor who has experienced such a recurrence — she may just be the first case that was recognized. When Cafferkey fell ill last week, it did not look like Ebola. In countries with with fragile or collapsed health systems, such as Sierra Leone, Liberia and Guinea — or the Democratic Republic of Congo or Uganda, which have also had Ebola outbreaks in the recent past — a resurgence of illness in survivors that did not resemble classic Ebola could easily have gone undetected. Poor medical records can further complicate the situation, making it hard for doctors to separate any new symptoms from pre-existing conditions.
With Cafferkey’s case confirming, for the first time, the ability of Ebola to reactivate in survivors, there are new concerns that other people may have died from undiagnosed relapses of Ebola, months after their initial recovery, and that more could still die.
‘Ebola-free’? Not quite…
Little is known about the long-term consequences of the disease, because earlier outbreaks Ebola outbreaks have been confined to rural, isolated locales, where they quickly burned themselves out by infecting everyone within a certain radius, then running out of new victims — leaving only sporadic case studies to guide clinicians. With more than 17,000 survivors in West Africa’s outbreak, however, researchers are ramping up investigations on complications.
And as doctors are now poignantly learning, saying a patient is “Ebola-free” doesn’t necessarily mean the virus is completely eradicated from the body. Indeed, on the same day that doctors announced news of Cafferkey’s relapse, the New England Journal of Medicine published a paper showing that the virus can be detected in semen for at least nine months after acute infection, much longer than previously estimated. A second study, also published this week in the New England Journal of Medicine, confirms the first known case of sexual transmission of Ebola, to a woman in Liberia. A preliminary report on the same incident was published in May, documenting how public health workers had identified the case through extensive contact tracing, but at the time, researchers were still working to verify the route of transmission. As detailed in this week’s study, the results of genetic testing confirmed that the female patient had been infected by a recent male sexual partner, who had recovered from Ebola seven months earlier.
Scientists already knew that Ebola could persist for some time in other tissues and fluids such as in the eye, the central nervous system, the prostate gland, the placenta, vaginal secretions, and breast milk, though the risk of transmission from these sites is even lower than for semen. But the discovery that the virus lingers in semen and is capable of causing disease months later is sobering. This could have been the reason why Ebola flared up again in Liberia in June after it was thought to be over. The same thing has happened during other outbreaks in past years.
The persistence of Ebola virus, or fragments of it, had already come under renewed scientific scrutiny for its possible role in ‘post-Ebola syndrome‘, a poorly understood range of symptoms including visual problems, joint and muscle pain, headaches and extreme fatigue that is experienced by about half of survivors in West Africa. Now, with evidence that the virus is capable of producing an active infection in survivors at least nine months after initial recovery, scientists are left racing to understand a disease that seems to become more complex at every turn. And with so many survivors potentially at risk, the stakes couldn’t be higher.