A new study has found that the Ebola virus, which can persist in some areas of the body, can re-emerge to cause severe disease even years after undergoing treatment with monoclonal antibodies, according to Medical Xpress.
The study, published Wednesday in the edition of Science Translational Medicine, used a nonhuman primate model of Ebola virus infection.
Senior author Dr. Xiankun (Kevin) Zeng said that some Ebola outbreaks in Africa have been associated with persistent infection in patients who had survived previous outbreaks.
Dr. Zeng is a principal investigator at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID).
In the 2021 outbreak in Guinea, a persistently infected survivor of the previous major outbreak at least five years ago re-emerged. However, the exact “hiding place” of the persistent Ebola virus and its underlying pathology were largely unknown.
Dr. Zeng explained, “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.”
“We found that about 20 percent of monkeys that survived lethal Ebola virus exposure after treatment with monoclonal antibody therapeutics still had persistent Ebola virus infection—specifically in the brain ventricular system, in which cerebrospinal fluid is produced, circulated, and contained—even when Ebola virus was cleared from all other organs,” he added.
Dr. Zeng and his team found that two monkeys that recovered from Ebola virus-related disease after undergoing antibody treatment had a recurrence of severe clinical signs of Ebola virus infection and died of the disease.
They found that severe inflammation and massive Ebola virus infection were present in the brain ventricular system, with no obvious pathology and viral infection found in other organs.
The researchers said that recurrence of the Ebola virus disease has previously been reported in human survivors.
For years, Dr. Zeng and his team at USAMRIID have performed systematic studies of Ebola virus persistence using nonhuman primate survivors. They found that the virus, despite being cleared from all other organs, can hide and persist in specific immune-privileged organs, such as the vitreous chamber of eyes, the seminiferous tubules of testes, and the ventricular system of the brain.
The study’s co-first author Dr. John Trefry said, “The persistent Ebola virus may reactivate and cause disease relapse in survivors, potentially causing a new outbreak.”
Ebola virus, one of the deadliest infectious diseases, is still a major public health threat in Africa. In 2021 alone, there were three outbreaks in Africa, according to the World Health Organization (WHO).
There are currently two vaccines and two monoclonal antibody therapies to prevent and treat Ebola virus disease. The antibody treatments are now part of the standard of care for Ebola-infected patients.
Dr. Zeng said, “Fortunately, with these approved vaccines and monoclonal antibody therapeutics, we are in a much better position to contain outbreaks. However, our study reinforces the need for long-term follow-up of Ebola virus disease survivors—even including survivors treated by therapeutic antibodies—in order to prevent recrudescence. This will serve to reduce the risk of disease re-emergence, while also helping to prevent further stigmatization of patients.”
