Authors: Martha Powell, Future Science Group
Research published recently in JAMA Neurology has investigated the persistence of Ebola virus in the central nervous system (CNS) and has suggested that the virus might be cell-associated within this system.
Since the outbreak in West African, much has been discovered about this virus, including clinical sequelae and the possibility of relapse and persistence. Neurological complications have become recognized as increasingly common with a potential for Ebola virus to persist in the CNS. One example is the case of a nurse who, 9 months after Ebola recovery, developed meningoencephalitis with seizures, radiculitis and cranial nerve involvement.
In this investigation, which was part of the PREVAIL study, the team examined the cerebrospinal fluid (CSF) of Ebola survivors using a lumbar puncture. The researchers collected samples from seven survivors – two women and five men – who had an average age of 35. All participants had reported neurological symptoms both during and after their stay in the Ebola Treatment Unit, including hallucinations, headache, tinnitus and tremor.
The group analyzed all samples for the presence of Ebola virus RNA, reporting that none was present in any of the seven samples.
The team postulated that there could be two explanations for this. Firstly, there was a long period of time between discharge from the Ebola Unit and enrolment in this study, ranging from 364–459 days. The authors wrote: “The CSF from all seven patients undergoing analysis was negative for Ebola viral RNA and showed no signs of inflammation; however, this finding could be related to the relatively long period from resolution of acute EVD to performance of lumbar puncture.”
Alternatively, the authors suggest that during its dormancy in the CNS, Ebola virus could be cell-associated – in which case it may not be released into the CSF. Additionally any release of virus from cell reservoirs into the CSF would be expected to cause meningoencephalitis, as observed in the mentioned case.
The authors concluded: “Thus, EVD survivors should be monitored for neurologic symptoms suggestive of EVD relapse in the CNS because of the potential for Ebola virus transmission during relapse.”
Sources: Billioux BJ, Nath A, Stavale EJ et al.Cerebrospinal Fluid Examination in Survivors of Ebola Virus Disease. JAMA Neurol. doi:10.1001/jamaneurol.2017.1460 (2017) (Epub ahead of print); www.eurekalert.org/pub_releases/2017-07/tjnj-cfo071317.php