The Viruses

Abstract

This report describes the taxa and member viruses approved by the ICTV between 1970 and 1993. Descriptions of the most important characteristics of these taxa are provided, together with a list of members and selected references. These descriptions represent the work of the chairpersons and members of the Subcommittees and Study Groups of the ICTV. A glossary of abbreviations and terms is provided first; followed by a set of virus diagrams and listings of the taxa, alphabetically, then by host, and then by nucleic acid and genome characteristics. A key to the placement of the viruses in the taxa is provided. Descriptions of the taxa and a listing of unassigned viruses follow.The names of orders, families and genera approved by ICTV are printed in italics. Names that have not yet been approved are printed in quotation marks in standard type. Vernacular species names, whether approved or not, are printed in standard type.Throughout the Report, three categories of member viruses of the various taxa have been defined: (1) Type species: pertains to the type species used in defining the taxon. As noted above, the choice of the type species by ICTV is not made with the kind of precision that must be used by international specialty groups and culture collections or when choosing substrates for vaccines, diagnostic reagents, etc. In this regard, the designation of prototype viruses and strains must be seen as a primary responsibility of international specialty groups. (2) Other species: pertains to those viruses which on the basis of all present evidence definitely belong to the taxon. (3) Tentative species: pertains to those viruses for which there is presumptive but not conclusive evidence favoring membership of the taxon.The ICTV has approved one order, 50 families, 9 subfamilies and 164 genera. Descriptions of virus satellites, viroids and the agents of spongiform encephalopathies (prions) of humans and several animal species are included. Finally a list of unassigned viruses is provided with a pertinent reference for each. In the synthesis of viral RNA, the term polymerase has been replaced in general by two somewhat more specific terms: RNA replicase and RNA transcriptase. The term transcriptase has become associated with the enzyme involved in messenger RNA synthesis, most recently with those polymerases which are virion-associated. However, it should be borne in mind that for some viruses it has yet to be established whether or not the replicase and transcriptase activities reflect distinct enzymes rather than alternative activities of a single enzyme. Confusion also arises in the case of the small positive-sense RNA viruses where the term replicase (e.g., Q~ replicase) has been used for the enzyme capable both of transcribing the genome into messenger RNA via an intermediate negative-sense strand and of synthesizing the genome strand from the same template. In the text, the term replicase will be restricted as far as possible to the enzyme synthesizing progeny viral strands of either polarity. The term transcri...

Baculoviruses contain a gene for the large subunit of ribonucleotide reductase.

“…Baculoviruses are pathogenic for arthropods and have a large (80-160 kbp) circular dsDNA genome (Murphy et al, 1995). They replicate in the nucleus of the infected cell.…”

Assembly of recombinant Newcastle disease virus nucleocapsid protein into nucleocapsid-like structures is inhibited by the phosphoprotein.

“…A member of the family Paramyxoviridae, NDV has recently been reclassified into the genus Rubulavirus (Murphy et al, 1995). Other members of this genus include mumps virus and simian virus 5 (SV5) in addition to the human parainfluenza viruses 2, 4a and 4b (hPIV2, 4a and 4b).…”

“…The genome of NDV, which comprises a single strand of negative-sense RNA, encodes directly six structural genes in the order 3h-NP-P-M- F-HN-L-5h (reviewed by Millar & Emmerson, 1988). Unlike SV5 and mumps virus, NDV does not encode the small hydrophobic (SH) protein between the F and HN genes (Murphy et al, 1995). Replication of the viral genome is dependent upon encapsidation of the RNA by the nucleocapsid protein (NP) which acts as a template for a polymerase complex comprising the large, polymerase protein (L) and phosphoprotein (P) cofactor (Hamaguchi et al, 1983).…”

Effect of Heparin on Infection of Cells by Equine Arteritis Virus.

“…Recently, we reported that the growth of bovine ephemeral fever, Kimberley, and Berrimah viruses of the family Rhabdoviridae, genus Ephemerovirus, Akabane virus of the family Bunyaviridae, genus Bunyavirus, and porcine reproductive and respiratory syndrome virus (PRRSV), a member of the genus Arterivirus [5] were inhibited by heparin [3,7].…”