Ebola virus (EBOV) persistence in asymptomatic humans and Ebola virus disease (EVD) sequelae have emerged as significant public health concerns since the 2013–2016 EVD outbreak in Western Africa. Until now, studying how EBOV disseminates into and persists in immune-privileged sites was impossible due to the absence of a suitable animal model. Here, we detect persistent EBOV replication coinciding with systematic inflammatory responses in otherwise asymptomatic rhesus monkeys that had survived infection in the absence of or after treatment with candidate medical countermeasures. We document progressive EBOV dissemination into the eyes, brain and testes through vascular structures, similar to observations in humans. We identify CD68+ cells (macrophages/monocytes) as the cryptic EBOV reservoir cells in the vitreous humour and its immediately adjacent tissue, in the tubular lumina of the epididymides, and in foci of histiocytic inflammation in the brain, but not in organs typically affected during acute infection. In conclusion, our data suggest that persistent EBOV infection in rhesus monkeys could serve as a model for persistent EBOV infection in humans, and we demonstrate that promising candidate medical countermeasures may not completely clear EBOV infection. A rhesus monkey model may lay the foundation to study EVD sequelae and to develop therapies to abolish EBOV persistence.

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The authors thank S. Lockett and K. Peifley at the Optical Microscopy and Analysis Laboratory, National Cancer Institute at Frederick (Fort Detrick, Frederick, MD, USA) for use of their confocal microscope. The authors thank L. Bollinger and J. Wada (NIH/NIAID Integrated Research Facility at Fort Detrick, Frederick, MD, USA) for critically editing the manuscript and figure preparation, respectively. The authors thank W. Discher and J. Braun at United States Army Medical Research Institute of Infectious Diseases (USAMRIID, Fort Detrick, Frederick, MD, USA) for the eye diagram and M. Kortepeter, A. Cardile, C. Shaia and A. Anderson for their critical reading of the manuscript. Work at USAMRIID was funded by The Joint Science and Technology Office for Chemical and Biological Defense (JSTO-CBD) of the Defense Threat Reduction Agency (DTRA) and the Medical Countermeasure Systems (MCS) of the Joint Program Executive Office for Chemical and Biological Defense (JPEO-CBD). This work was supported in part through Battelle Memorial Institute's prime contract with the US National Institute of Allergy and Infectious Diseases (NIAID) under contract no. HHSN272200700016I. A subcontractor to Battelle Memorial Institute who performed this work is: J.H.K., an employee of Tunnell Government Services, Inc. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the US Department of the Army, the US Department of Defense, the US Department of Health and Human Services, or of the institutions and companies affiliated with the authors. In no event shall any of these entities have any responsibility or liability for any use, misuse, inability to use, or reliance upon the information contained herein. The US departments do not endorse any products or commercial services mentioned in this publication.

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  1. United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, Maryland 21702, USA

    • Xiankun Zeng
    • , Candace D. Blancett
    • , Keith A. Koistinen
    • , Christopher W. Schellhase
    • , Jeremy J. Bearss
    • , Sheli R. Radoshitzky
    • , Shelley P. Honnold
    • , Taylor B. Chance
    • , Travis K. Warren
    • , Jeffrey W. Froude
    • , Kathleen A. Cashman
    • , John M. Dye
    • , Sina Bavari
    • , Gustavo Palacios
    •  & Mei G. Sun
  2. Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, B-8200 Research Plaza, Frederick, Maryland 21702, USA

    • Jens H. Kuhn


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X.Z. conceived and designed the experiments. X.Z. and C.D.B. performed the in situ hybridization. X.Z. performed the immunofluorescence staining and confocal imaging. K.A.K., C.W.S., J.J.B., S.P.H. and T.B.C. performed histopathology. T.K.W., J.W.F., K.A.C., J.M.D. and S.B. provided experimental materials. X.Z., S.R.R., G.P. and J.H.K. interpreted the data and wrote the manuscript. S.B. and M.G.S. coordinated and oversaw the study.

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The authors declare no competing financial interests.

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Correspondence to Xiankun Zeng.

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