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CLASSIFICATION
OF
VIRUSES
CHAPTER 2
Prepared by Miss Rashidah Hj Iberahim
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CONTENT
Naming of viruses
Criteria used in classification of viruses
Baltimore classification
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Viral specificity
 Capable to infecting all forms of life (hosts)
 However, a range of virus could only specify infecting
a certain range of hosts
 Viral specificity is the specific kinds of virus that can
infect specific cell – papillomavirus can only infect skin
cell
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Criteria of classification
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Reasons beyond classification
 Classification of virus been determined by the
structural and chemical composition of virus
 Are apply to all plant viruses, animal viruses and
bacterial viruses
 Virus is acellular cell – cannot be categorised using
taxonomic classification
 It used International Committee on Taxonomy of
Viruses (ICTV) to classify the viruses
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Examples
Animal virus
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Plant virus
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Before discovery
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Dermotropic – infected skin cell
Neurotrophic – infected nerve cell
Viscerotropic – infect organ of digestive tract
Pneumotropic – infected respiratory system
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After discovery
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Type and structure of their nucleic acids
Methods of replication
Host range
Chemical and physical characteristics
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Type and structure of their nucleic
acids
 RNA virus
(+) sense
(-) sense
double stranded
 DNA virus
single stranded
double stranded
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RNA viruses (+ve sense)
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Picornaviridae
Togaviridae
Flaviviridae
Retroviridae
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RNA viruses (-ve sense)
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Paramyxoviridae
Rhabdoviridae
Orthomyxoviridae
Filoviridae
Bunyaviridae
Reoviridae (double-stranded)
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DNA viruses
Double – stranded
 Adenoviridae
 Herpesviridae
 Poxviridae
 Papovaviridae
 Hepadnaviridae
Single – stranded
o Parvoridae
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