NEI Team Studying Ebola’s Impact on the Eye|
A team of clinicians and technical experts from the National Eye Institute is traveling to Monrovia, Liberia to investigate the long-term effects of Ebola on the eye among hundreds of survivors following the 2014 outbreak in West Africa that led to 11,200 deaths in the region.
NEI’s investigation is part of a larger study called PREVAIL III (Partnership for Research on Ebola Vaccines in Liberia) sponsored by NIAID and the Liberian Ministry of Health. The goal is to understand the long-term health implications of Ebola virus disease among those who survived acute infection with the virus, many of whom report a variety of ailments from headaches and tinnitus, to joint and muscle pain, eye fatigue and blurry vision.
While physicians have some understanding about how to manage the infection during the acute phase, their strategies are experimental and much is still unknown about the natural history of Ebola virus, including in the eye and its long-term effects on ocular health and vision, said Dr. Rachel Bishop, chief of the consult services section at NEI and part of the NIH team in Liberia.
Ebola lingers in the eye after a person recovers from the acute illness and the blood is virus-free, a fact that Bishop emphasizes does not put other people at risk of becoming infected because the virus is inside the eye, not on the surface. Nor is there any evidence that live virus is present in survivors’ tears. But transmission associated with the eye could be a potential concern in the future if eye surgery should be needed.
Based on literature reports from the 1990s, it was anticipated that some survivors of the latest Ebola epidemic would develop uveitis, an inflammatory eye disease. However, “at this point we don’t know the extent of the effect of Ebola on the eye,” said Bishop. “We’ve seen changes to nearly every part of the eye among Ebola survivors, including many changes in the retina [the light-sensitive part of the eye]. And some survivors are having vision problems such as difficulty focusing and eye fatigue, the causes of which remain elusive.” In addition, some Ebola survivors show signs of cognitive changes after the infection, which could also contribute to vision difficulties, she said.
Conducted at multiple sites in Liberia, PREVAIL III will aim to enroll 7,500 people, including 1,500 survivors and up to 6,000 of their close contacts to serve as controls. The findings may help determine if survivors are immune from future Ebola infections and will assess the risk of transmitting the virus to close contacts and sexual partners. In addition to the eye, the virus appears to persist in the testes; semen can carry live virus months after recovery and clearance from the blood.
The NEI team will periodically return to Liberia, where it is assisted by a local team including nurses, technicians and administrative support staff. Liberian ophthalmologists provide follow-up care for participants needing treatment.
“Despite the tragedy that the Liberians have endured, you get a sense of positive energy and liveliness—so it’s actually a happy place to work. It’s a true collaboration,” Bishop said.
The Liberians are also grateful, said NEI’s Guy Foster, chief of the clinical services section, who helped set up the clinic equipment. Recalling an ophthalmologist working at an outlying clinic, he said, “This man was used to sticking a flashlight on top of the slit lamp to examine his patients’ eyes. No LED bulbs. No electricity. The ocean air corrodes the equipment so nothing really functions well and yet they are still trying to see patients. I showed him what we are doing in the clinic and he hugged me. He said ‘Now I can treat patients. I was about to give up.’”