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27 Cards in this Set

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