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21 Cards in this Set

  • Front
  • Back
What is the difference between orthomyxovirus genome and paramyxovirus genome?
1. Orthomyxovirus genome - segmented (-) ssRNA
2. Paramyxovirus genome - nonsegmented (-) ssRNA
What are orthomyxoviruses two external glycoprotiens?
1. Hemagglutinin (HA)
2. Neuraminidase (NA)
What orthomyxovirus glycoprotein binds to sialic acid and functions in virus-cell attachment? What recognizes it and what is it important in?
1. Hemagglutinin
2. Antibodies
3. Antigenic drifting
What orthomyxovirus glycoprotein cleaves sialic acid and prevents the clumping of orthomyxovirus? Why is this important?
1. Neuraminidase
2. Without neuraminidase,a virus would stick to cell surface sialic acid residues when it buds.
Where does orthomyxovirus genome replication take place? How is this different than paramyxovirus?
1. It takes place in the host cell nucleus.
2. Paramyxovirus genome replication takes place in the host cell's cytoplasm.
Where does the initial innoculation of orthomyxovirus take place?
In the epithelium of the lungs
What are three complications of orthomyxovirus infection?
1. Secondary bacterial infection due to the damage to the respiratory epithelium
2. Viral pneumonia
3. CNS and muscle involvement
How are the designations of type A and B orthomyxovirus different?
Type B orthomyxovirus does not have a HA or NA designation.
Can orthomyxovirus migrate from animal to humans?
Yes - bird flu for example
What are the two main ways antigenic change occurs in orthomyxovirus?
1. Antigenic shift
2. Antigenic drift
What is antigenic shift? What can be used as a mixing pot for antigenic shift?
1. Results from the reassortment of genome segments resulting in virus strains.
2. Pigs or humans can both have two forms of a virus (bird and human virus) and allow the sharing of genomes to produce a new strain of virus
What is antigenic drift?
Results from individual nucleuotide substitutions in the HA and NA genome allowing for changes in antigenicity. These nucleotide changes can result from mistakes made by RNA polymerase.
What is the main consequence of antigenic shift? Antigenic drift?
1. Pandemic orthomyxovirus strains
2. The need for new orthomyxovirus vaccines from year to year
What disorder was seen when people gave asprin to children with the flu to bring their fever down?
Reye's Syndrome - encephalopathy
How would you describe the managment of orthomyxovirus infections?
Mainly supportive care including oxygen.
What two drugs that interfere with M2 protein to block viral uncoating in the cell are used as antivirals? What is the problem with these drugs?
1. Amantidine
2. Rimantadine
3. Viral resistance
What are two new drugs that interfere with neuraminidases in order to control infection?
1. Zanamivir
2. Oseltamivir
What is a problem already seen with oseltamivir?
Strains of virus resistant to the drug have been recovered from people with avian flu virus.
What are the two forms of orthomyxovirus vaccines?
1. Inactivated vaccine - dead flu virus that works very well
2. Nasal-spray flu vaccine - live attenuated virus
What are the three orthomyxovirus strains that are usually included in the orthomyxovirus vaccine right now?
1. Strain A (3H2N)
2. Strain A (1H1N)
3. Strain B
When an animal is carrying a new strain of virus, what is usually done?
The animal is slaughtered.