British nurse Pauline Cafferkey is in critical condition in a London hospital, suffering complications of the Ebola she caught while working in West Africa last December. She seemed to have recovered from the virus in January, but her case shows how little we understand about the dangers of the Ebola virus, even now as the epidemic wanes.
Even after someone has recovered from Ebola, the virus can remain in parts of the body that are sheltered from the immune system, such as the testis, the eye and breastmilk. It now seems that the virus can persist in human testes for at least nine months after it has stopped circulating in a person’s blood, and is detectable in semen.
Cafferkey sought medical help on 7 October for non-specific viral symptoms. Despite her history, she was sent home, and wasn’t admitted to an isolation ward until three days later. She tested positive for the Ebola virus, and now 58 close contacts, including medical staff, are under surveillance. Some have received an experimental Ebola vaccine.
Post-Ebola syndrome
Cafferkey is not the only Ebola survivor who is ill. More than half of the estimated 17,000 people in West Africa who survived the virus are thought to be experiencing a range of ill health, including severe headaches, joint pain and fatigue.
While it has been confirmed that Cafferkey is still carrying the Ebola virus, it is not yet clear whether these other people are. Their illnesses could be caused by damage to their immune systems, or by copies of the virus that have hung on in their bodies. If they do still have the virus, it is unclear whether it can spread.
The research by the team in Sierra Leone shows that the virus can be detected in the semen of male survivors up to nine months after recovery, but did not determine if this virus is intact or infectious. But another team has published evidence today that a survivor in Liberia did transmit the virus sexually, in semen, last March. Such cases could make it harder to finally snuff out the West African epidemic.
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As well as the testes, the brain, eyes and joints may also provide sheltered sites for the virus to hide from the immune system. A study in August found that survivors of an Ebola outbreak in Uganda in 2007 are now more likely to suffer severe headaches and neurological problems, including disturbed sleep and hearing or memory loss.
A quarter of survivors of the West African epidemic have suffered severe eye inflammation, probably caused by the virus persisting inside the fluid in the front of their eyeballs. But fortunately, unlike the testes, this hiding place does not seem to be letting the virus escape. When virologists examined a US medical worker who had post-Ebola eye problems, they found no virus in his tears or on the surface of his eye, suggesting that he was unlikely to be infectious.
Long-term effects
So far, Cafferkey is the only confirmed person for whom post-Ebola syndrome has been life-threatening. However, medics who worked during the epidemic say there have also been cases in West Africa.
“We now have an opportunity, and a responsibility, to learn as much as we can about what happens to Ebola survivors,” says Dan Bausch of Tulane University in New Orleans, who is working on Ebola with the World Health Organization in Geneva. The organisation is planning to assemble data collected by medical teams during the West African epidemic to resolve the mystery.
US medical agencies are recruiting Ebola survivors in Liberia for a study of post-Ebola syndrome, aimed at discovering what causes it, and whether such lurking virus can spread. Several other groups of survivors are being recruited to look at long-term effects of having had Ebola, says John Edmunds of the London School of Hygiene and Tropical Medicine. This information will be vital to the West African countries that are trying to rebuild their healthcare systems, and which could be dealing with survivors’ complications for many years.
If there have been other cases of severe illness just months after surviving the virus, like Cafferkey, in West Africa, we may never know. Medical systems there are still in disarray, and these people are likely to have died.
Journal references: New England Journal of Medicine, DOI: 10.1056/NEJMoa1511410; DOI: 10.1056/NEJMoa1509773
