Phylogenetic tree comparing ebolaviruses and marburgviruses. Numbers indicate percent confidence of branches. The Ebola virus is a member of the Filovirus family. These are single-stranded RNA viruses. Philoviruses are the longest at about 1000 nanometers. Ebola is a single-stranded RNA virus containing 19,000 nucleotides. It encodes seven structural proteins: nucleoprotein ( NP), polymerase cofactor ( VP35), (VP40), GP, transcription activator ( VP24), and RV24 transcription activator ( VP30). L)