Sketchy Micro: Orthomyxovirus

Question 1

What kind of virus is Orthomyxovirus?

Answer 1

• ssRNA, negative sense (like the warm orange tones, but it’s night-time now!)
• Enveloped (like the orthodontist’s white coat)
• Segmented (like the octopus’s eight arms!)

Note: all negative-sense RNA viruses are single-strand except Reovirus

Question 2

All negative-sense RNA viruses bring their own ______________.

Answer 2

RNA polymerase

Question 3

All RNA viruses replicate in _____________.

Answer 3

the cytoplasm, except Orthomyxovirus which replicates in the nucleus

(To represent this, the baby octopuses are inside the helmet.)

Question 4

The most common Orthomyxovirus is ___________.

Answer 4

Influenzae

Think of the sign advertising “FLUoride… it’s as easy as ABC!”

Question 5

How many segments does the Orthomyxovirus have?

Answer 5

Eight (like the octopus’s eight arms)

Question 6

What is antigenic drift?

Answer 6

Slow point mutations that confer resistance

Think of the sign for Doktor Drift – the one incorrect letter is meant to show drift.

Question 7

What is antigenic shift?

Answer 7

Sudden reassortment of segments (like the H that is falling in “Night Shift” that is reassorting with letters on the bottom of the sign)

Question 8

Antigenic shift occurs only in strain _____.

Answer 8

A

Question 9

Hemagglutinin is a ______________.

Answer 9

glycoprotein found on the surface of Influenzae that binds to sialic acid on RBCs

(The octopus represents HA that is sticking to the RBCs. Notice that the green material looks like carbohydrates sticking off of RBCs.)

Question 10

What prevents future infection with the same strain?

Answer 10

Antibody to hemagglutinin

Question 11

What is M2?

Answer 11

A protein that alters the pH of endocytosed flu particles, allowing for their release

If you inhibit M2–which amantadine and rimantadine do –then flu virus will not be released.

(Think of the octopus hiding in the clam. The clam has two ridges that look like M. The MANTa ray DINing is scaring the octopus back into the clam.)

Question 12

Give an indication for amantadine.

Answer 12

Not used due to widespread resistance, amantadine is only effective in the A strain

Question 13

Why is neuraminidase needed?

Answer 13

Without neuraminidase, the newly created virions will get stuck to the outside of the cell membrane.

Question 14

Which drug inhibits neuraminidase?

Answer 14

oseltamivir (Tamiflu)

(Think of assistant TAMmy capping the scalpels that the octopus might use to free her babies from the sialic acid seaweed.)

Question 15

Flu season peaks during _____________.

Answer 15

December to February

Question 16

Which flu vaccine is live?

Answer 16

The intranasal form (think of the skeleton with the needle through his chest)

Question 17

The flu vaccine covers which strains?

Answer 17

A and B

Question 18

What is a common complication of Influenzae?

Answer 18

Bacterial pneumonia (represented by the orthodontist’s golden staph)

Question 19

What are two sign and symptoms of Reye syndrome?

Answer 19

Fatty liver failure and encephalitis (like the fat cow with the liver spot and the guy with the red turban on the bottle of aspirin near the aquarium)

Question 20

What is the biochemical basis of Reye syndrome?

Answer 20

Aspirin uncouples the proton gradient of hepatic mitochondria

Question 21

What CSF values are typical of Guilain-Barre syndrome?

Answer 21

High protein with low WBC

Question 22

Influenzae can also cause _____________.

Answer 22

Guilain-Barre syndrome (like the bear on the kid’s lap)