Scientists have discovered new information regarding the prolonged presence of the Ebola virus in the body even after apparent recovery. Studies revealed that the virus could stay active and infectious in laboratory-grown brain-like structures for an extended period, shedding light on why some survivors experience severe complications years later.
Ebola virus disease is a severe and potentially fatal infection characterized by symptoms such as fever, vomiting, bleeding, and organ failure. Although some patients survive the acute phase of the illness, it has been known for some time that the virus can persist within the body.
Researchers suspect that past Ebola outbreaks might have been triggered by carriers who harbored the virus long after recovery. A recent outbreak in Guinea in 2021 was traced back to a survivor from the 2014-16 epidemic, indicating the virus could have remained dormant in the body for over five years before resurfacing.
A recent study published in Nature Microbiology proposes that the brain could serve as a sanctuary where the virus evades the immune system’s defenses. Scientists from the Icahn School of Medicine at Mount Sinai and the Bernhard Nocht Institute for Tropical Medicine, along with international collaborators, utilized miniature lab-grown brain organoids made from human stem cells to examine post-infection behavior. These organoids mimic human brain tissue, providing insights into how the virus interacts within such an environment.
The findings showed that Ebola and related viruses could infect the brain-like tissue and replicate for up to 120 days without remaining dormant. The virus actively spread between cells, generating infectious viral particles despite the immune response mounted by the infected tissue being insufficient to eradicate the virus completely.
Persistent infection may contribute to the development of complications such as eye, meninges, or brain inflammation in Ebola survivors. In rare instances, relapses have occurred months or even years after apparent recovery, with researchers identifying genetic alterations that support the virus’s extended survival in the body.
Lead author Dr. Lina Widerspick emphasized that studying these mechanisms in organoids enables a deeper understanding of how filoviruses persist in the human central nervous system and potentially lead to severe complications like meningoencephalitis in Ebola survivors.
While Ebola continues to pose a significant threat in certain regions of Africa, the researchers anticipate that their discoveries could enhance survivor treatments and offer insights into the emergence of future Ebola outbreaks from persistent infections. They also aim to broaden their investigations to encompass other viruses.