In vivo characterization of the novel ebolavirus Bombali virus suggests a low pathogenic potential for humans

Emerg Microbes Infect. 2023 Dec;12(1):2164216. doi: 10.1080/22221751.2022.2164216. Epub 2023 Jan 18.


Ebolaviruses cause outbreaks of haemorrhagic fever in Central and West Africa. Some members of this genus such as Ebola virus (EBOV) are highly pathogenic, with case fatality rates of up to 90%, whereas others such as Reston virus (RESTV) are apathogenic for humans. Bombali virus (BOMV) is a novel ebolavirus for which complete genome sequences were recently found in free-tailed bats, although no infectious virus could be isolated. Its pathogenic potential for humans is unknown. To address this question, we first determined whether proteins encoded by the available BOMV sequence found in Chaerephon pumilus were functional in in vitro assays. The correction of an apparent sequencing error in the glycoprotein based on these data then allowed us to generate infectious BOMV using reverse genetics and characterize its infection of human cells. Furthermore, we used HLA-A2-transgenic, NOD-scid-IL-2γ receptor-knockout (NSG-A2) mice reconstituted with human haematopoiesis as a model to evaluate the pathogenicity of BOMV in vivo in a human-like immune environment. These data demonstrate that not only does BOMV show a slower growth rate than EBOV in vitro, but it also shows low pathogenicity in humanized mice, comparable to previous studies using RESTV. Taken together, these findings suggest a low pathogenic potential of BOMV for humans.

Keywords: Bombali virus; ebolavirus; filovirus; full-length clone; humanized mice; pathogenic potential; reverse genetics; virulence.

MeSH terms

  • Africa, Western
  • Animals
  • Animals, Genetically Modified
  • Ebolavirus* / genetics
  • Hemorrhagic Fever, Ebola*
  • Humans
  • Mice
  • Mice, Inbred NOD

Grants and funding

This work was supported by the Friedrich-Loeffler-Institut under the grant VISION, by the German Center for Infection Research under the grant TTU 01.702, by a research grant from the Chica and Heinz Schaller Foundation (Schaller Research Group Leader Program), by the German Research Foundation (DFG) under the grant 469065579, and by the German Ministry of Food and Agriculture based on the decision of the Parliament of the Federal Republic of Germany through the Federal Office for Agriculture and Food under the Grant Ebola-Foresight.