Forty years after the first Ebola outbreak in the Democratic Republic of Congo, investigators find that a small group of survivors are still producing virus-fighting antibodies.
In a significant new study, researchers have found that some Ebola virus survivors continue to produce antibodies to the virus nearly 4 times longer than previously believed, potentially granting them with lifelong immunity.
The first 2 outbreaks of Ebola virus occurred in 1976 in South Sudan and a village in the Democratic Republic of Congo (DRC), near Africa’s Ebola river. What we now know is that fruit bats are the likely natural hosts of the virus, according to the World Health Organization (WHO). Humans contract Ebola from close contact with the blood, secretions, organs, or other bodily fluids of infected wild animals such as chimpanzees, gorillas, fruit bats, and monkeys, as well as from human-to-human contact. Symptoms Ebola can appear 2 to 21 days after exposure to the highly contagious virus and can include fever, severe headache, muscle ache, diarrhea, vomiting, and hemorrhaging. Although there are currently no antiviral drugs or vaccines for Ebola approved by the United States Food and Drug Administration (FDA), early medical intervention can boost the chances of survival from the deadly disease, and drug treatments and vaccines are in the pipeline.
There were 318 cases and 280 deaths in the first DRC outbreak, which had a fatality rate of 88% and left 38 survivors. In a new study published in The Journal of Infectious Diseases, an international team led by University of California, Los Angeles investigators returned to the DRC and tracked down 14 survivors of the original outbreak, who at the time of the study ranged in age from 55 to 86 years old.
The study team’s goal was to learn more about the impact Ebola had on survivors 4 decades after infection. They traveled to small, remote villages in the DRC’s Équateur Province to collect blood samples from the survivors and used an enzyme-linked immunosorbent assay to measure the Ebola antibodies present in their blood.
While previous studies documented antibody responses in Ebola survivors for as long as 11 years after infection, this study was the first to find antibodies persisting for as long as 40 years. In addition, 4 survivors still had antibodies able to neutralize the virus, a finding that could be key to helping researchers develop treatments and vaccines for Ebola.
“Unimaginable death tolls and devastation to families and communities have occurred as a result of Ebola,” said lead author Anne Rimoin, PhD, MPH, in a recent press release. “With the number and frequency of Ebola outbreaks increasing over time, the need to find effective measures to combat and prevent outbreaks is critical.”
There are more than 11,000 survivors from the largest Ebola outbreak to date, which occurred from 2014 to 2016 and heavily impacted Guinea, Liberia, and Sierra Leone. Dr. Rimoin and her team are continuing to study the survivors of the original outbreak to learn more about the long-term health effects of Ebola infection.