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27 Cards in this Set
- Front
- Back
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What two groups are picornaviruses usually broken down into?
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1. Enteroviruses
2. Rhinoviruses - common cold |
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What is the route of entry into the body for enterovirus?
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Fecal-oral
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Why is enterovirus good for GI transmission?
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It is stable in an acid enviroment.
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What is the polio virus receptor? Where is infection limited to because of this receptor?
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1. CD155
2. GI Tract and CNS |
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How is enterovirus usually aquired (what fecal-oral route)?
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1. Directly from contaminated water
2. From shellfish that were in contaminated water |
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What is rhinovirus' cellular receptor?
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ICAM-1
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What is Coxsackievirus' cellular receptor?
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Coxsackievirus-Adenovirus Receptor
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Where does primary infection from enterovirus take place?
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The mucosa and lymphoid tissue of the GI tract.
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When do you end up with the more severe symptoms of enteroviruses?
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In the few cases where the primary infection sheds into the blood to cause viremia and it can then spread to secondary sites of infection.
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What are the usual secondary sites of infection in enterovirus?
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1. Liver - Hep A
2. Meningies - echovirus coxsackievirus and poliovirus 3. Brain - coxsackievirus or poliovirus 4. Muscle tissue surrounding the heart - echovirus and coxsackievirus 5. Skin - echovirus and coxsackievirus |
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Why do coxsackievirus and echovirus seem to show up in a bunch of tissues in secondary sites of infection?
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Their cellular recptors are much more widespread.
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How many days after contraction does it take to see shedding of poliovirus in the feces?
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12 days
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What percentage of the time does poliovirus progress to CNS involvement and paralysis?
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1. 1% to 2% of the time for non-paralytic
2. 0.1% to 2% for paralytic |
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When do the paralytic symptoms show up if you are going to have them?
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3-4 days after the initial minor symptoms
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Why does poliovirus only cause motor dysfunction?
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The CD155 receptors are only present in the motor nuerons in the brain and spinal cord.
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What role do antibodies play in polio?
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Upon previous exposure by vaccine or previous infection, antibodies can prevent viremia.
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Which domain of the CD155 receptor is responsible for sticking into the viral capsid?
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The outer domain (domain 3)
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What is the problem seen in post-polio syndrome?
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The new neurons that sprout to make up for the lost neurons end up being weak and degenerating over time.
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What are the two types of poliovirus vaccines?
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1. Salk vaccine (IPV) - dead poliovirus
2. Sabin vaccine (OPV) - live attenuated virus - RNA mutation prevents viral replication in the CNS |
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What is a problem with the Sabin poliovaccine?
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It has a tendancy to revert back to being virulent.
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What is a key difference in poliovirus replication and rhinovirus replication?
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Rhinovirus is not stable in an acid enviroment like poliovirus is so it does not replicate in the GI tract.
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Where is the primary site of infection in rhinovirus?
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Usually the respiratory tract
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What is the cellular recptor for rhinovirus?
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ICAM-1
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What temperature does rhinovirus like to replicate at? Enterovirus?
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1. 33C - likes the cooler enviroment of the lungs
2. 37C |
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Rhinovirus tends to exacerbate what condition?
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Asthma
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Why is rhinovirus a virus that we would like therapeutics for?
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We don't have sufficient antibodies for all the serotypes plus with all the serotypes, vaccination would be impossible.
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What are some possible targets of rhinovirus replication?
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1. Binding to ICAM-1
2. Uncoating process 3. Protease cleavage 4. RNA replication (RNA dependent RNA polymerase) 5. Assembly and release |
