DESCRIPTION OF VIRUSES

Family Filoviridae

Genus “Ebola-like viruses”

Genus “Ebola-like viruses”

Type Species

Zaire Ebola virus

(ZEBOV)

Distinguishing Features

1.

Almost no antigenic cross-reactivity with Marburg virus,

2.

Virion length is about 970  nm as opposed to 790  nm with Marburg virus,

3.

Genome length of 18.9  kb as opposed to 19.1  kb with Marburg virus,

4.

Several gene overlaps as opposed to a single overlap with Marburg viruses,

5.

Glycoprotein expression involves transcriptional editing,

6.

Transcription of only the first ORF of gene four yields a soluble small glycoprotein not observed with Marburg virus,

7.

Protein profile distinct from Marburg virus; however, species-specific,

8.

Glycoprotein gene nucleotide difference of 57% compared with Marburg virus,

9.

Fatality rates for humans 50 to 90% with species Sudan Ebola virus and Zaire Ebola virus, respectively. Species Reston Ebola virus appears to be nonpathogenic for humans.

List of Species Demarcation Criteria in the Genus

Virus species in the genus may be distinguished on the basis of their glycoprotein gene sequence differences (more than 30% amino-acid difference, see Table 2), cross-protection data (where available) and differences in geographic origins.

List of Species in the Genus

Official virus species names are in italics. Tentative virus species names, alternative names ( ), strains or serotypes are not italicized. Virus names, location and date of isolation ( ), genome sequence accession numbers [ ], and assigned abbreviations ( ) are:

Species in the Genus

Cote d’Ivoire Ebola virus

(CIEBOV)

Strain Cote d’Ivoire (Tai Forest, 1994);

Reston Ebola virus

(REBOV)

Strain Reston (1989)

Strain Philippines (1989)

Strain Siena (1992)

Strain Texas (1996)

Sudan Ebola virus

(SEBOV)

Strain Boniface (1976)

Strain Maleo (1979)

Zaire Ebola virus

(ZEBOV)

Strain Mayinga (Zaire, 1976)

Strain Zaire (Zaire, 1976)

Strain Eckron (Zaire, 1976)

Strain Tandala (1977)

Strain Kikwit (1995)

Strain Gabon (1994-1997)

Tentative Species in the Genus

None reported.

Unassigned Viruses in the Family

None reported.

Phylogenetic Relationships within the Family

See Fig. 3.

Similarity with Other Taxa

Comparison of filovirus genomes with other Mononegavirales demonstrates a similar structure and suggests comparable mechanisms of transcription and replication. Comparative sequence analyses of single genes indicate that filoviruses are phylogenetically quite distinct from other families of the order Mononegavirales. Limited homology exists between the carboxy-terminal part of filovirus GP and the trans-membrane p15E-related glycoproteins of oncogenic retroviruses.

Derivation of Names

Ebola: from Ebola river in Zaire where one of the first registered outbreaks of the disease occurred.

Filo: from Latin filum, “thread”, to indicate the morphology of virus particles.

Marburg: from Marburg, town in Germany, where the first known outbreak of filovirus disease occurred and where filoviruses have been discovered.


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