Ebola Infection Remains for Extended Period After Treatment, Scientists Say

After seemingly recovering from Ebola, the infection can persist for an extended period in the brain and other parts of the body, according to scientists at the U.S. Army Medical Research Institute of Infectious Diseases. An article published in the journal Science Translational Medicine states that research conducted on monkeys has shown that the virus remains active and can cause lethal and infectious disease again.

It has long been known that the Ebola virus can cause persistent infections, which have been associated with outbreaks of hemorrhagic fever in Africa. However, until now, scientists did not know the exact locations of the pathogen's persistence within the human body. It is known that the virus can hide even after treatment with monoclonal antibodies, a standard therapy used in Ebola infections.

In this new study, scientists used a monkey model that more accurately replicates the course of the infection in humans. It was found that 20 percent of rhesus monkeys that survived initial Ebola virus infection and were treated with monoclonal antibodies had persistent infection; the pathogen was discovered in the brain's ventricular system, where cerebrospinal fluid circulates. The virus was found to be harbored within macrophages in the ventricles, leading to severe inflammation and cell death.

In two of the monkeys, scientists observed a recurrence of hemorrhagic fever with severe clinical symptoms, which ended in the animals' deaths. Interestingly, the infection did not spread to other organs apart from the brain.

The study's press release noted that similar cases have also been observed in humans. For instance, a British nurse developed meningoencephalitis nine months after recovering from Ebola, and another patient who was treated with monoclonal antibodies died from a recurrence six months later, leading to the infection of others.

According to scientists, this emphasizes the need for long-term monitoring of patients, even if it seems they have already recovered from hemorrhagic fever.