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?

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.

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.

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

D e n so v irus

Ite ra v irus

B re v id e n so v irus

P e fun d en sov irus

D e n sov irin ae(S u b fa m ily)

M V M

C a n ine p a rvo v irusC P V

P o rc ine p a rvo v irusP P V

Parvovirus

A A V s-1 -?

G o ose pa rvov irusG P V

A v ia n A A VA A A V

Dependovirus

P a rvov irus B 19B 1 9V

S im ian p a rvo v irusS P V

P m P V

Erythrovirus

B o v in e pa rvov irusB P V

M inute v iru s of canine sM V C

Bocavirus

A le u tio n d ise a se(m in ks )

Amdovirus

Parvovirinae(S u b fa m ily)

Parvoviridae(F a m ily )

+ +

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)

Servant et al. J. Virol 2002

V9

A6

Phylogenetic tree of VP1u region

Phylogenetic analysis of capsid proteins of the Parvovirinae

Phylogenetic analysis of non-structural proteins of the Erythroviruses

Nucleotide Substitutions (x100)0

148.0

20406080100120140

A6-NSV9-NSB19-NSRhPV-NSSPV-NSPtPV-NSBPV-3-NSChip-NSBPV-2-NSPPV-H1-NSAAV2-Rep78MVM-NS

Percent Identity NS proteins

0

500

1000

1500

2000

2500

3000

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 100

Percent

Genus

Species

Strains

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

D e n so v irus

Ite ra v irus

B re v id e n so v irus

P e fun d en sov irus

D e n sov irin ae(S u b fa m ily)

M V M

C a n ine p a rvo v irusC P V

P o rc ine p a rvo v irusP P V

Parvovirus

A A V s-1 -?

G o ose pa rvov irusG P V

A v ia n A A VA A A V

Dependovirus

P a rvov irus B 19B 1 9V

S im ian p a rvo v irusS P V

P m P V

Erythrovirus

B o v in e pa rvov irusB P V

M inute viru s of canine sM V C

H u m an b o ca v irus

Bocavirus

A le u tio n d ise a se(m in ks )

Amdovirus

Parvovirinae(S u b fa m ily)

Parvoviridae(F a m ily )

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)