Selective Replication and Vertical Transmission of Ebola Virus in Experimentally Infected Angolan Free-Tailed Bats

In spite of the continuous sporadic Ebola virus (EBOV; Orthoebolavirus zairense) disease outbreaks with associated devastating public health, economic, and wildlife impacts for nearly five decades in Africa, a convincing natural reservoir host, as well as mechanisms of virus circulation in nature or spill over to humans are yet to be identified.  Bats have been reported as reservoirs of many zoonotic viruses including filoviruses, and experimental infections are often vital for understanding reservoir-pathogen interactions. Therefore, in this study, the permissiveness of Angolan free-tailed bats (AFBs) known to harbour filoviruses, to Ebola, Marburg, Taï Forest and Reston viruses was assessed. The experiment revealed that only the AFBs inoculated with EBOV showed marked disseminated viral replication, and shed infectious EBOV without displaying obvious clinical signs, as the other filoviruses failed to establish productive infections. In addition, the EBOV was shown to possess a unique placental-specific tissue tropism, and traversed the placental barriers to infect and persist in the AFBs foetal tissues resulting in distinct genetic signatures of adaptive evolution. Thus, AFBs reservoir competence, plausible transmission routes, and possible ancillary transmission mechanism that might be required to maintain EBOV within small reservoir populations have been described.
(BNU)