The filoviruses contain at least seven structural proteins, all of which are translated from monocistronic polyadenylylated mRNA transcripts. Among the seven viral gene products, the glycoprotein (GP) is central to the virus life cycle. This protein is synthesized in two forms: one, as a structural protein that is incorporated into the virion and the second that is secreted (sGP), with distinct biological functions. Virion GP forms trimers, binds preferentially to endothelium and has been used to 'pseudotype' a mouse retroviral vector that facilitates gene transcripts preferentially to these cells (Yang et al., 1998). During pseudotyping studies, there was a decrease in virus titer, and the altered cell morphology in retrovirus producer cells when the level of expression of Ebola GP was increased, but not the murine leukemia virus envelope glycoprotein. These findings indicate that the Ebola glycoprotein might directly contribute to cellular cytotoxic effects.

The surface glycoprotein (GP) is expressed from the fourth of the seven structural protein genes. Because filoviruses contain a single transmembrane GP that forms spikes on the virion surface, the GP is most likely to be responsible for receptor binding and membrane fusion, leading to virus penetration. Filovirus GP is a type I glycoprotein, containing both N-linked and O-linked carbohydrates which contribute to considerably larger molecular weights than those predicted from deduced amino acid sequences.

Potential reservoirs of Zaire ebolavirus are fruit bats of the species Hypsignathus monstrosus, Epomops franqueti, and Myonycteris torquata which are present in large parts of West Africa. Therefore, it is possible that Zaire ebolavirus has circulated undetected in this region for some time (Leroy et al., 2005).