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Spring, 2004 Lecture Outline

2/17 TAXONOMY & SYSTEMATICS


Taxonomy: ICTV- International Committee on Taxonomy of Viruses

working to standardize nomenclature

nomenclature: formal- Linneas scheme of family, genus, & species

E.g.: Family Poxviridae, subfamily Chordopoxvirinae, genus Orthopoxvirus, vaccinia virus
informal- "the pox family", "poxviruses"

individual virus identification must be unambiguous: ICTV oversees & catalogues; international specialty groups & agencies establish designations [ATCC, WHO]

Systematics: ICTV established systematic organization & keying scheme

"Universal System of Virus Taxonomy"
-assignment of families, subfamilies, genera, species
-only one order established so far: Mononegavirales

universal virus database [ICTVdb]: expected to be complete before the end of the decade [except for ongoing new entries]

"Name That Virus" game: Introduction to primary characteristics & keying schemes for viruses- Be sure to bring your CRC book; other materials will be handed out


Summary of significant criteria:

DNA/RNA; ss or ds; +/- reverse transcriptase; +/-/ambisense [RNA]
linear/circular/segmented genome; genomic size
host type; helical/cubic/bisymmetric; +/- envelope/peplomers
virion size; filamentous/rod/spherical; specific enzymes/proteins
type of ORF/transcription/translation; type of budding [envelope]
+/- vector & type of vector

Characteristics not important taxonomically: pathology & cytopathic effects- several unrelated viruses may cause same or similar effects

closely related viruses may cause very different effects
same virus may cause very different effects in different hosts or host cells


Essentials to know on specific viruses:

structure of virion; genomic structure & major gene products
replication strategy; transcription/translation strategy
assembly/release characteristics; unique characteristics
prototype or representative virus

where appropriate: transmission; host[s]; path/cytopath; diseases; symptoms; diagnosis; treatment; useful applications

Next up: Non-enveloped [+] strand RNA viruses

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 Updated 1/25/04 by thatcher@sonoma.edu