According to a recent study, the Ebola virus can persist in the brain for years and re-emerge as a fatal disease.
Since its discovery in 1976, the Ebola virus has caused several outbreaks across West Africa. The 2014-2016 outbreak was the world’s largest Ebola outbreak, claiming more than 11,000 lives. Later in 2020, the Democratic Republic of Congo (DRC) announced an end of an Ebola epidemic in the area. The World Health Organization (WHO) called it the world’s second-deadliest Ebola outbreak. According to research, a case of Ebola relapse likely caused the transmission of multiple cases during the epidemic. Thus, causing scientists to hypothesize that the virus likely persists in the body after treatment. However, the virus’s exact hiding spot has remained unclear. Now, researchers at the U.S. Army Medical Research Institute of Infectious Diseases have discovered that the Ebola virus hides in the brain for years after infection.
Ours is the first study to reveal the hiding place of brain Ebola virus persistence and the pathology causing subsequent fatal recrudescent Ebola virus-related disease in the nonhuman primate model.
Dr Xiankun (Kevin) Zeng, senior author
Is Treatment Still Effective?
The team of researchers used a nonhuman primate model to discover the virus’s hiding spot. They took samples from 36 rhesus macaques with a history of Ebola infection and that had received treatment with monoclonal antibodies. Next, the team analyzed their organs for traces of the virus. According to the results, 20% of these monkeys had a persistent Ebola virus infection. Despite clearance of the virus from other organs, it remained in the brain ventricular system. Moreover, two of the monkeys died from a re-emergence of the virus within the brain. Thus, proving that people who receive antibody treatments are at risk of disease resurgence.
The persistent Ebola virus may reactivate and cause disease relapse in survivors, potentially causing a new outbreak.
Dr. Jun Liu, study author
Although the disease is often fatal, with a 50% case fatality rate, vaccinations have played a key role in increasing survival. Moreover, treatment with monoclonal antibodies has also proved successful in treating the disease. While the current therapeutics remain effective at containing outbreaks, study authors call for a long-term follow-up of Ebola survivors. Thus, preventing re-emergence. However, there is a need for clinical testing in humans as the current study is based on primates.
Reference:
Ebola Virus Persistence and Disease Recrudescence in the Brains of Antibody-Treated Nonhuman Primate Survivors. Liu et al., Sci. Transl. Med.14, eabi5229 (2022) 9 February 2022. https://www.science.org/doi/10.1126/scitranslmed.abi5229
