Detection of Viral RNA in Tissues following Plasma Clearance from an Ebola Virus Infected Patient

An unprecedented Ebola virus (EBOV) epidemic occurred in 2013–2016 in West Africa. Over this time the epidemic exponentially grew and moved to Europe and North America, with several imported cases and many Health Care Workers (HCW) infected. Better understanding of EBOV infection patterns in different body compartments is mandatory to develop new countermeasures, as well as to fully comprehend the pathways of human-to-human transmission. We have longitudinally explored the persistence of EBOV-specific negative sense genomic RNA (neg-RNA) and the presence of positive sense RNA (pos-RNA), including both replication intermediate (antigenomic-RNA) and messenger RNA (mRNA) molecules, in the upper and lower respiratory tract, as compared to plasma, in a HCW infected with EBOV in Sierra Leone, who was hospitalized in the high isolation facility of the National Institute for Infectious Diseases “Lazzaro Spallanzani” (INMI), Rome, Italy. We observed persistence of pos-RNA and neg-RNAs in longitudinally collected specimens of the lower respiratory tract, even after viral clearance from plasma, suggesting possible local replication. The purpose of the present study is to enhance the knowledge on the biological features of EBOV that can contribute to the human-to-human transmissibility and to develop effective intervention strategies. However, further investigation is needed in order to better understand the clinical meaning of viral replication and shedding in the respiratory tract.
Author Summary An unprecedented Ebola outbreak occurred in 2013–2016 in West Africa. In order to better understand EBOV infection patterns in different body compartments, we have longitudinally explored the presence of already assessed markers of ongoing EBOV replication (negative sense genomic RNA and positive sense RNA) in the upper and lower respiratory tract, as compared to plasma and other body compartments, in a Health Care Worker infected with EBOV in Sierra Leone, who was hospitalized in the high isolation facility of the National Institute for Infectious Diseases “Lazzaro Spallanzani” (INMI), Rome, Italy. The presence of total EBOV RNA and replication markers was observed in specimens of the lower respiratory tract, even after viral clearance from plasma, suggesting possible local replication. Our results contribute to the knowledge on the biological features of EBOV and shed light on the potential role of respiratory compartment in human-to-human transmissibility.