Respiratory viruses

Question 1

what is the most common cause of upper respiratory tract infection? what family of viruses is this?

Answer 1

Rhinovirus (gives you the common cold), which is an RNA picornavirus

Question 2

why is there no vaccine for rhinovirus?

Answer 2

bc there are over 100 serological subtypes

Question 3

the fact that there are 100 serological subtypes of rhinovirus means what two thing?

Answer 3

1. no vaccine

2. you can be infected with it over and over

Question 4

rhinovirus is synonymous with…

Answer 4

the common cold

Question 5

unlike all other picornoviruses, rhinovirus is…

Answer 5

acid labile, which means that the virus is destroyed by stomach acid/bile and can’t cause GI ifxns

Question 6

what does it mean that rhinovirus, unlike all other picornoviruses, is acid labile?

Answer 6

it means that rhinovirus gets destroyed in the stomach, and has no GI side effects. All other picornoviruses infect the GI tract!

Question 7

influenza virus, which causes respiratory symptoms, is RNA or DNA? is ss or ds? enveloped or not? is what group?

Answer 7

ssRNA virus, enveloped, orthomyxovirus

Question 8

the influenza virus codes for what two proteins

Answer 8

Hemagglutinin (viral entry)

Neuraminidase (progeny virion release)

Question 9

the influenza virus makes what protein for viral entry

Answer 9

hemagglutinin

Question 10

the influenza virus makes which protein for progeny virion release?

Answer 10

neuraminidase

Question 11

what is hemagglutinin

Answer 11

protein made by influenza virus that allows for viral entry into the cell

Question 12

what is neuraminidase?

Answer 12

protein made by influenza virus for progeny virion release

Question 13

influenza’s segmented genome allows it to…

Answer 13

recombine with other strands of influenza—> increase virulence, lead to genetic shifts (when it’s combined with RNA from another species!) (pandemics)

Question 14

genetic drifts are caused by

Answer 14

point mutations in the genome

Question 15

what’s worse a genetic shift or drift?

Answer 15

genetic shift (pandemic)
genetic drift (epidemic)

Question 16

which virus group mainly infects children, giving them respiratory problems? what are the 4 subtypes of that virus group?

Answer 16

Paramyxovirus

1. parainfluenza (croup)
2. Mumps
3. Measles
4. RSV

Question 17

which paramyxovirus causes croup?

Answer 17

parainfluenza

Question 18

which paramyxovirus causes bronchiolitis in babies

Answer 18

RSV (respiratory syncytial virus)

** syncytial comes from the fact that surface F (fusion) protein on the virus causes respiratory epithelial cells to fuse, forming multinucleated giant cells (syncytial cells).

Question 19

paramyxoviruses (parainfluenza, measles, mumps and RSV) contain was virulence factor? what does it do?

Answer 19

surface F (fusion) protein– causes respiratory epithelial cells to fuse, forming multinucleated giant cells (syncytial cells).

Question 20

Do we get vaccinated for influenza A to protect us from genetic shift or drift?

Answer 20

Drift– minor changes in surface antigens due to point mutations. Though shift occurs (recombinant dna), the reality is that our vaccines can’t really protect against them.

Question 21

is influenza a live vaccine or a killed one?

Answer 21

killed

Question 22

can an immunocompromised pt get a flue vaccine?

Answer 22

yes, bc it’s a killed vaccine.

Question 23

how many segments in influenza virus?

Answer 23

8

Question 24

the fact that influenza is segmented (8 segments) means that it can undergo

Answer 24

genetic reassortment (where segments are switched in and out)