Picornavirus
5 important questions on Picornavirus
What is a picornavirus?
- Family picornavirus, genus enterovirus: Poliovirus/Rhinovirus
- Non-enveloped (+)ssRNA
- VPg virion protein is liked to the genome, which directs translation of the mRNA
- 4 structural proteins: 3 capside, 1 inside capside
- 7 non-structural proteins: RNA polymerase,...
- VP1 variable between enteroviruses and used to identify which virus it is
- UTR 5' is not variable, since transcription starts there
How does poliovirus infect the host? Other enteroviruses?
- Enter body through mouth
- Replicates in the intestine where it can also enter the bloodstream
- attack the central nervous system (CNS) - spinal cord
- destruction of nerve cells causes paralysing
- Exit through feces (get into water maybe - infection elsewhere)
Other enteroviruses
- entry through mouth
- reproduction in oropharynx and intestine - mucosal surfaces
- lymph nodes
- blood
- multiple organs: skin, muscle, brain/meninges
Difference and similarities between enterovirus and rhinovirus
- acid resistant (survive passage through the stomach
- replication intestine
- chronic infections possible
Rhinovirus
- acid sensitive
- replication respiratory tract
- no chronic infectins
Both humoral immunity plays a major role: acute, self-limiting
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What is the life cycle of Enterovirus
- Entry via receptor - polio: CD155
- DNA transcribed in cytosom
- Polio protein cleaved to get from one long polypeptide multiple proteins
What vaccine are against polio?
- Inactivated: injection
- Attenuated: oral (possible nutation to neurovirulence)
1 serotype, which implies a high degree of similarity in the surface antigens across all MV stains
Lot of variation due to mutation and/or recombination (with part of other virus from same family Enterovirus possible)
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