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Parvovirus Classification
Kevin E Brown
Immunisation and Diagnosis Unit
Virus Reference Department
Centre for Infections
Classification of Viruses
Prior to 1966 an array of different names/classifications
Moscow 1966 – International Congress of Microbiology
International Committee on Taxonomy of Viruses (ICTV)
A single taxonomic scheme for all viruses
Naming and classification
70 Study Groups who provide the information
Regular reports (currently 8th)
ICTV classification
‘a virus species is a polythetic class of viruses that
constitute a replicating lineage and occupy a particular
ecological niche’ (7th report)
Polythetic class - several properties in common, but not
necessarily a single common defining property
Hierarchy of recognised viral taxa:
(Order); Family; (Subfamily); Genus; Species
‘Other groupings (from clade to super-family), may
communicate useful descriptive information in some
circumstances but they have no formally recognized
taxonomic meaning’ (8th report, p4)
Demarcation criteria:
When is a new virus a new virus?
Since viruses are polythetic, multiple demarcation criteria are needed
to reliably delineate different species.
Sequence comparisons are an increasingly dominant (but not the only)
criteria.
Pairwise sequence identity
profiles: well resolved peaks
between strains, species and
genera. Different virus families
show similar overall patterns.
Genetic analysis should provide
validation of taxonomic
assignments.
Parvoviridae
Non-enveloped
22-24nm icosahedral virion
4 - 5.6 kb ss linear DNA genome
ITRs at 5’ and 3’ ends
Encode no polymerase
Dependant on cellular/other viral proteins for DNA
replication
2 large ORF
NS (or Rep) proteins
VP (or Cap) proteins
Parvovirus Classification
Host range -2 subfamilies
Densovirinae – insects
Parvovirinae – vertebrates
Autonomous/dependant replication
+ , –, or +/- strand packaging
Identical or different 5’ and 3’ ITRs
1, 2 or 3 promoters
Sequence phylogeny
Parvovirus Taxonomy
Parvoviridae
(Family)
Densovirinae
(Sub family)
Densovirus
Parvovirinae
(Subfamily)
Parvovirus
Dependovirus
Erythrovirus
Bocavirus
Amdovirus
Iteravirus
MVM
AAVs-1-?
Parvovirus B19
B19V
Bovine parvovirus
BPV
Canine parvovirus
CPV
Goose parvovirus
GPV
Simian parvovirus
SPV
Minute virus of canines
Porcine parvovirus
PPV
Avian AAV
AAAV
PmPV
Brevidensovirus
Pefundensovirus
+
+
MVC
Aleution disease
(minks)
Erythrovirus Genus
Encapsidate equivalent numbers of + and – strand
upon extraction anneal to form ds DNA
Long palindromic ITR (~383 nt)
‘Identical’ ITR at 5’ and 3’ ends
Single mRNA promoter
Polyadenylation signals mid genome and 3’ end
Efficient replication in erythroid precursors
Human Parvovirus B19 (B19V)
Type member of the Erythrovirus family
First identified in 1974 (CPHL, London)
~ 22 nm icosahedral virion
Linear ss DNA
~ 5600 nucleotides
Long (383nt) terminal hairpin seq
Complex transcription map
• Single promoter (p6)
• 1 non-spliced non-structural protein
• 2 capsid proteins (VP1 & VP2) -alt splicing
• Small proteins of unknown function
VP2 self assembles to form VLP
Erythrotropic
Does not grow in standard tissue culture
Replicates in erythroid progenitors
Rare cell lines (UT7/Epo; KU812Ep6)
A6
V9
Phylogenetic tree of VP1u region
Servant et al. J. Virol 2002
Phylogenetic analysis of capsid proteins
of the Parvovirinae
Phylogenetic analysis of non-structural
proteins of the Erythroviruses
A6-NS
V9-NS
B19-NS
RhPV-NS
SPV-NS
PtPV-NS
BPV-3-NS
Chip-NS
BPV-2-NS
PPV-H1-NS
AAV2-Rep78
MVM-NS
148.0
140
120
100
80
60
Nucleotide Substitutions (x100)
40
20
0
Percent Identity NS proteins
3000
2500
Genus
Species
2000
Strains
1500
1000
500
0
1
4
7
10
13
16
19
22
25
28
31
34
37
40
43
46
49
52
P er cent
55
58
61
64
67
70
73
76
79
82
85
88
91
94
97
100
List of species in Erythrovirus genus
Type species – human parvovirus B19
Accepted species
•
•
•
•
•
Human parvovirus B19 (B19V)
B19V-A6, B19V-Au, B19V-LaLi, B19V-V9, B19V-Wi
Pig-tailed macaque parvovirus (PmPV)
Rhesus macaque parvovirus (RmPV)
Simian parvovirus (SPV
Tentative species
• Bovine parvovirus type 3 (BPV-3)
• Chipmunk parvovirus (ChpPV)
Human Parvoviruses
Parvoviridae
(Family)
Densovirinae
(Sub family)
Densovirus
Parvovirinae
(Subfamily)
Parvovirus
Dependovirus
Erythrovirus
Bocavirus
Amdovirus
Iteravirus
MVM
AAVs-1-?
Parvovirus B19
B19V
Bovine parvovirus
BPV
Canine parvovirus
CPV
Goose parvovirus
GPV
Simian parvovirus
SPV
Minute virus of canines
Porcine parvovirus
PPV
Avian AAV
AAAV
PmPV
Human bocavirus
Brevidensovirus
Pefundensovirus
MVC
Aleution disease
(minks)
Parv4/5
Parvovirus Study Group
Peter Tattersall, Max Bergoin, Marshall Bloom, Kevin Brown,
Michael Linden, Nick Muzycka, Colin Parrish and Peter Tijssen
Dr Anne Field
(1936-2007)