Genome - ssRNA, negative polarity, linear, no poly-A tails, not capped,
19.1 kb (largest negative strand RNA virus).
Capsid - enveloped, helical in symmetry, long filamentous shape,
constant diameter of 80 nm, hollow axial channel (20 nm), helical
periodicity every 10 nm (approximately)
Proteins - 7 associated structural and regulatory proteins
- L - RNA dependent RNA polymerase
NP - nucleocapsid protein
GP - glycoprotein
(note: 2 forms exist: (1) envelope associated transmembrane form (Ebola-Zaire); (2) soluble form (sGP) (Ebola-Zaire).
VPs - 4 glycosylated viral proteins
Envelope - contains virally encoded glycoprotein spikes
EM Morphology - filaments, circles, Us, 6s, 9s
Replication - in the cytoplasm
Virulence - up to 88% mortality (Zaire outbreak)
Biosafety level - P-4 containment
Ecology - Africa
Epidemiology - Man is incidental host
Transmission - often associated with body fluid contact. No known
reservoir or host.
The genus Filovirus can be separated into two distinct species, Marburg
and Ebola. These differ in their glycoprotein genes by at least 55% at the
DNA level and by 67% at the amino acid level. While different subspecies
(genotypes) have not been qualified for Marburg, many are described for
Ebola, including: Ebola Sudan, Ebola Zaire, Ebola Reston, and Ebola Cote
D'Ivoire. Each of these subspecies differs from heterlogous types by 37% -
41% at the DNA level (GP gene) and by 34% - 43% at the amino acid
(GP) level.