+ Strand Viruses Flashcards
Discuss Poliovirus replication
- Initial replication is in mucosal and lymphoid cells.
- Secondary replication in the spinal cord, DRG, skeletal muscle.
- Receptor binding causes a change in virion structure; injecting viral RNA directly into cytoplasm.
What is the role of viral replicase in poliovirus?
Makes a minus strand, which is used to make another plus strand.
What are plus strands used for in poliovirus?
- Synthesize protein
- Template for minus strand
- packaged into newly formed virions
Is poliovirus cytolytic or lysogenic?
Cytolytic; released by cell lysis.
Discuss poliovirus pathogenesis
- Entry into mouth
- Replication in pharynx, GI tract
- Hematologic spread to lymphatics and CNS
- Spread along nerve fibers
- Destruction of motor neurons.
Describe Groups A and B Coxsackieviruses
Transmitted via fecal-oral route. Causes itchy throat, dysphagia
Describe Coxsackieviruses B clinical manifestation
- Myocaridits
- Pleurodynia
- Meningitis
Describe Noroviruses
Non-enveloped; Spread via fecal-oral route. Self-limiting, rehydration therapy
Describe Rotaviruses
Survives GI environment; NSP4 protein has cholera toxin like activity
What is the shape of coronaviruses?
Helical
Discuss coronavirus proteins
E1: Budding and envelope formation E2: Receptor N: nucleoprotein, binds RNA Polymerase: RNA dependent RNA polymerase HI: Hemagglutinin
Discuss the gene expression of coronaviruses
- Translation of polymerase from genomic RNA
- strand is made via polymerase
- strand is made
- Translation of additional viral proteins from mRNAs
- Genome associtation with N protein
- Budding of virus into ER and release by exocytosis.
How are coronaviruses transmitted?
Aerosols and droplets
Discuss SARS
Causes viral pneumonia involving lower respiratory tract; Fever, dry cough, dyspnea, hypoxaemia
