Many survivors of the 2014-2016 Ebola outbreak in West Africa have ongoing health problems, a new study finds.
More than 28,000 people were infected and more than 11,000 died in the outbreak.
Researchers compared 966 Ebola survivors from Liberia with 2,350 close contacts and sexual partners. They found that survivors were more likely to have increased urinary frequency, headaches, fatigue, as well as neurological and musculoskeletal problems.
Memory loss was reported in 30 percent of survivors, compared to fewer than 6 percent of their contacts. Survivors reported twice as much joint and muscle pain.
While 25 percent of survivors have uveitis -- an inflammation of the eye that can lead to blindness -- it was also found in 12 percent of the contacts. Researchers said that suggests Ebola may not be its cause.
They also discovered that Ebola virus genetic material can be found intermittently in the semen of male survivors for more than three years.
"We found many examples where people would test negative twice for Ebola and then later test positive. Some people would go through multiple episodes of this up to 40 months or possibly longer after being infected with Ebola," study co-leader Cavan Reilly said. He is a professor at the University of Minnesota School of Public Health in Minneapolis.
"However, it's not likely that they're contagious and can infect other people," Reilly said in a university news release.
"The findings suggest there's a great need to provide follow-up care for Ebola survivors to help them deal with lingering health problems," Reilly added. "The study results could also help improve the response to the current Ebola epidemic underway in the Democratic Republic of the Congo."
The findings were recently published in the New England Journal of Medicine.
Reilly's team plans to keep tracking the health of the Ebola survivors at least through 2020. The researchers are also working on a study to evaluate the effectiveness of several treatments for active Ebola infection.
The U.S. Centers for Disease Control and Prevention has more on Ebola.