Ebola May Leave Survivors with Lasting Problems in Brain, Nerves
Particles of Ebola virus (Zaire) obtained from cell culture fluid.
Credit: Elena Ryabchikova, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Science

Although experts recently declared the world's largest Ebola outbreak over, many people who were infected with the virus are still experiencing neurologic problems, according to a new study.

Researchers found that, among a group of 82 Ebola survivors in Liberia, nearly all had some neurologic problems at six months or longer after they were infected.

"While an end to the outbreak has been declared, these survivors are still struggling with long-term problems," study author Dr. Lauren Bowen, a neurologist at the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, said in a statement.

More than 28,600 people were infected with the virus in West Africa during the outbreak, and 11,300 of those people died, Bowen said. In the new study, the researchers wanted to find out whether, among the 17,000 survivors of the infection, there were people still experiencing brain or other neurological health problems, she said. [Where Did Ebola Come From?]

The researchers looked at 82 people in Liberia who were infected during the outbreak. Each patient in the study underwent a neurological examination. The researchers also asked the participants about their neurological symptoms, both while the individuals were being treated for Ebola and after their treatments were over.

The neurological exams showed that about two-thirds of the participants had abnormalities in the way their eyes followed moving objects. Such abnormalities "normally indicate a subtle degree of damage in the brain," Bowen told Live Science.

One-third of the people had tremors, abnormal reflexes and other sensory abnormalities, and 17 percent had certain reflexes that are typically signs of disorders affecting the frontal lobes of the brain.

Other common neurologic symptoms reported in the study were headaches, depressed mood, weakness, muscle pain and memory problems; 21 people in the study said they'd had hallucinations.

Twenty people in the study experienced meningitis (inflammation of the tissue that surrounds the brain and spinal cord), either while they were being treated for Ebola or after they left the treatment unit. And 14 people had been in a coma at some point, Bowen said.

Some of the most common symptoms the people were experiencing at the time of the study included weakness, headaches, memory problems, depressed mood and muscle pain. Two people said they felt suicidal.

The researchers said there is not enough known about these problems to say with certainty which of them might be due to Ebola. And the scientists noted that the study did not have a control group, which would be a group of uninfected patients.

Further research that does include a control group is ongoing, the researchers said. They are also going to follow up with the survivors for several more years to see if their neurologic symptoms persist, or whether the people's conditions improve over time, said study co-author Dr. Bridgette Jeanne Billioux, a neurologist in Baltimore, Maryland.

It is also not clear how Ebola may contribute to these neurologic symptoms, the researchers said. However, the symptoms may be related to the significant blood loss that often occurs in Ebola patients, and the effects of this loss on the brain, Bowen said.

The new results will be presented in April at the American Academy of Neurology's 68th Annual Meeting in Vancouver, Canada. The findings have not been published in a peer-reviewed scientific journal.

Follow Agata Blaszczak-Boxe on Twitter. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.