Persistent Ebola virus infection can be detected in rhesus monkeys that survive the disease and no longer show symptoms, reports a paper published online this week in Nature Microbiology. This experimental model using rhesus monkeys, whose reaction to the virus is similar to that of humans, may lay the foundation to study persistent Ebola virus disease and its related long-term effects, and to develop new treatments.
Ebola virus persistence refers to the presence of the virus in specific tissues (such as the eyes, brain and testes) of disease survivors who no longer show symptoms. Persistence and its long-term effects (such as loss of vision, headaches and joint pain) have emerged as significant public health concerns since the 2013-2016 outbreak in Western Africa, which was unprecedented in its size and spread. In addition to long-term symptoms of disease, persistence is problematic because it can lead to new infections, as seemingly cured people can still transmit the virus. However, until now, studying how Ebola disseminates in a host and persists in survivors was impossible due to the absence of a suitable animal model.
Xiankun Zeng and colleagues find that Ebola virus spreads through the blood vessels and can be detected in the eye, brain and testes of rhesus monkeys that have survived Ebola disease and no longer have symptoms. In the eye, the virus is found in macrophages that express the protein CD68 on their surface, which might be where the virus hides during the latent phase, the research suggests. The authors also find that virus persistence occurs in monkeys that have received experimental antiviral treatments, suggesting that candidate medical treatments may not completely clear Ebola virus infection.