viruses Article Tolerance and Persistence of Ebola Virus in Primary Cells from Mops condylurus, a Potential Ebola Virus Reservoir Marcel Bokelmann 1 , Uwe Vogel 1 , Franka Debeljak 2 , Ariane Düx 3 , Silke Riesle-Sbarbaro 1 , Angelika Lander 1 , Annette Wahlbrink 1 , Nicole Kromarek 1 , Stuart Neil 2 , Emmanuel Couacy-Hymann 4 , Joseph Prescott 1 and Andreas Kurth 1, *   Citation: Bokelmann, M.; Vogel, U.; Debeljak, F.; Düx, A.; Riesle-Sbarbaro, S.; Lander, A.; Wahlbrink, A.; Kromarek, N.; Neil, S.; Couacy- Hymann, E.; et al. Tolerance and Persistence of Ebola Virus in Primary Cells from Mops condylurus,a Potential Ebola Virus Reservoir. Viruses 2021, 13, 2186. https:// doi.org/10.3390/v13112186 Academic Editor: Ayato Takada Received: 20 August 2021 Accepted: 26 October 2021 Published: 29 October 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Centre for Biological Threats and Special Pathogens, Robert Koch Institute, 13353 Berlin, Germany; Marcel.Bokelmann@fli.de (M.B.); VogelU@rki.de (U.V.); Riesle-SbarbaroS@rki.de (S.R.-S.); LanderA@rki.de (A.L.); wahlbrinka@rki.de (A.W.); kromarekn@rki.de (N.K.); prescottj@rki.de (J.P.) 2 Department of Infectious Diseases, King’s College London, London WC2R 2LS, UK; franka.debeljak@kcl.ac.uk (F.D.); stuart.neil@kcl.ac.uk (S.N.) 3 Epidemiology of Highly Pathogenic Microorganisms, Robert Koch Institute, 13353 Berlin, Germany; DuexA@rki.de 4 Laboratoire National d’Appui au Développement Agricole, Bingerville BP 206, Côte d’Ivoire; chymann@gmail.com * Correspondence: KurthA@rki.de Abstract: Although there have been documented Ebola virus disease outbreaks for more than 40 years, the natural reservoir host has not been identified. Recent studies provide evidence that the Angolan free-tailed bat (Mops condylurus), an insectivorous microbat, is a possible ebolavirus reservoir. To investigate the potential role of this bat species in the ecology of ebolaviruses, replication, tolerance, and persistence of Ebola virus (EBOV) were investigated in 10 different primary bat cell isolates from M. condylurus. Varying EBOV replication kinetics corresponded to the expression levels of the integral membrane protein NPC1. All primary cells were highly tolerant to EBOV infection without cytopathic effects. The observed persistent EBOV infection for 150 days in lung primary cells, without resultant selective pressure leading to virus mutation, indicate the intrinsic ability of EBOV to persist in this bat species. These results provide further evidence for this bat species to be a likely reservoir of ebolaviruses. Keywords: Ebola virus; reservoir host; bat; virus replication; tolerance; persistent infection 1. Introduction Ebolavirus and Marburgvirus are genera within the family Filoviridae in the order of Mononegavirales [1]. Six species within the Ebolavirus genus have been discovered: Zaire, Sudan, Taï Forest, Bundibugyo, Reston and, most recently, Bombali ebolavirus. Of these six species, only four viruses (Ebola virus, Sudan virus, Taï Forest virus, and Bundibugyo virus) are known to cause severe hemorrhagic fever in humans with case fatality rates up to 90% [1–3]. Since 1976, 29 ebolavirus outbreaks have been documented in Africa. The largest outbreak, occurring in 2014–2016, was caused by Ebola virus (EBOV), resulting in over 28,600 cases and 11,300 deaths [4]. Outbreak investigations and several epidemiological studies provide evidence that several bat species are the likely natural reservoir hosts for ebolaviruses [5,6]. For multiple outbreaks, there is anecdotal evidence of index patients contacting bats prior to infec- tion [5,7–10]. Various species of wild-caught bats have tested seroreactive for EBOV, with antibodies being detected in 307 individual bats from 17 species in Africa and Asia [5,11–20]. Almost all of these studies have focused on frugivorous bats, while insectivorous microbats have received only sparse attention in ebolavirus research [21]. With EBOV replication without signs of illness after experimental infection [22], detection of EBOV-specific anti- bodies [13] and a potential contact with the index case of the large EBOV outbreak in West Viruses 2021, 13, 2186. https://doi.org/10.3390/v13112186 https://www.mdpi.com/journal/viruses