Common Viral Pathogens II

Question 1

What is the basic structure, important proteins, and protein functions in the Influenza virus?

Answer 1

Structure: 8 segments of ssRNA. Lipid envelope.

Proteins: H (hemaglutin) and N (Neruoaminidase)
-eg H1N1 flu.

Fxn:
H- Involved in “H”ost cell attachment and cell entry.
N: Releases the virus from the infected cell

Question 2

There are 2 types of Flu strains each year. Which type can infect animals other than humans?

Answer 2

TYPE A

A is for Animal

Question 3

Which type of Flu strain is usually a more severe illness?

Answer 3

TYPE A

Remember how you didn’t want to get Swine Flu (H1N1)?

Question 4

Which type of Flu strain can cause both Epidemics AND Pandemics?

Answer 4

TYPE A again.

This type A flu is really bad A$$.

Question 5

Guess which type of flu strain can rapidly mutate?

Answer 5

TYPE B!

Psych…

Its really Type A again.

Question 6

What is the most H and N proteins a flu has been found to have?

Answer 6

H16 N9

Question 7

What is the basic structure, important proteins, and protein functions in RSV (respiratory syncytial virus)?

Answer 7

Structure: Non Segmented ssRNA (types A and B).

Proteins: F and G protein

Fxn:
F= Fusion of Envelope to Host Membrane
G= Initial bindinG of virus to host cell

Question 8

Which type of RSV is more severe, A or B?

Answer 8

A again… This is getting old.

Question 9

How does influenza enter the body?

Answer 9

Through the Mucosal Surfaces

Eyes, nose, mouth

Question 10

How does RSV enter the body?

Answer 10

Through conjunctiva and nasopharynx.

Infects lower respiratory tract.

Question 11

T/F: The flu vaccine is made on a “best guess” of what the flu virus will look like in the upcoming year.

Answer 11

True:

The flu mutates so quickly that a vaccine for this year will be different than last year. Sometimes we predict the flu wrong and then it sucks…

Question 12

How do we treat the flu?

Answer 12

1. Matrix Protein Inhibitors (type A virus)
   eg amantadine
2. Neuraminindase Inhibidors (both A and B)
   eg Oseltamivir and Zanamivir

There is high resistance to antivirals

Question 13

What are the 2 types of vaccines we give for the flu?

Answer 13

Inactivated influenza vaccine (IIV) for older than 6mo.

Live attenuated (LAIV)- 2-49

They are 70-90% effective in a “matched” year.

Moral of the story is, wash your hands because the vaccine can be useless some years.

Question 14

Which flu Vaccine is given to pregnant and immune compromised individuals?

Answer 14

Inactivated (IIV)

Question 15

How do you determine if a flu pandemic is occurring?

Answer 15

1. Emergence of a new influenza subtype
2. The virus must infect humans and cause serious illness
3. Virus must have sustained human-to-human transmission and spread easily (without interruption) among humans.

Question 16

T/F: Antigenic drift cause subtype change in flu viruses.

Answer 16

False

Question 17

Antigenic Shift occurs when______

Answer 17

A type A influenza virus with a completely novel hemagglutinin or neuraminidase gene segment is introduced into humans.

Question 18

H5N1 is aka Bird flu, is transmitted via close contact infected birds. The current attack rate in humans has been low. Why are we “concerned” about bird flu?

Answer 18

It could have a mutation in the binding to match a human (Alpha 2-6) configuration and cause a pandemic.

OR it could cause a pandemic via reassortment via pigs as the mixing vessel between humans and birds.

Question 19

Why is H5N1 not considered a pandemic?

Answer 19

It has not shown sustained “human to human” transmission and spread easily.

Question 20

How do we prevent RSV?

Answer 20

• There are No vaccines currently.
• We use immunoprophylaxis with palivizumab and motavizumab antibodies.
• Very expensive

Basically, we don’t really prevent it very well.