Influenza

Question 1

what type of virus is influenza

Answer 1

ssRNA, enveloped, helical nucleocapsid, 8 segment genome

Question 2

surface antigens on influenza

Answer 2

A or B, H (hemagglutinin), and N (neuraminidase

Question 3

antigenic drift

Answer 3

minor antigenic changes based on random mutations of either hemagglutinin or neuraminidase, cause epidemics

Question 4

antigenic shift

Answer 4

reassortment of segments of viral genome which lead to a new virus to which the population has no immunity, cause pandemics, more deadly

Question 5

why did mostly young people get effected by H1N1 in 2009

Answer 5

the H1N1 flu subtype had previously come in the early 1920s (Spanish flu) and the 70’s (Russian flu), so a lot of the older population had already developed immunity to it

Question 6

how do viruses get deposited on respiratory tract

Answer 6

inhaled, attach to epithelium, penetrate columnar epithelial cells

Question 7

what safeguards are in place to prevent the attachment of pathogens to the epithelial lining of the respiratory tract

Answer 7

specific secretory antibodies IgA, nonspecific mucoproteins, mechanical ciliary action

Question 8

viral infection leads to viral replication leads to cell death leads to

Answer 8

release of the virus, initiating infection of the adjacent cell

Question 9

incubation period of influenza virus

Answer 9

1-4 days

Question 10

illness duration of influenza virus

Answer 10

2-5 days

Question 11

viral shedding

Answer 11

1 day before symptoms, for a total of 6 days

Question 12

transmission of influenza virus

Answer 12

large droplet, close contact with infected person, can only travel 6 feet, possible small respiratory or from fomites

Question 13

fomites

Answer 13

inanimate objects that serve as a vector for infection

Question 14

clinical symptoms of influenza

Answer 14

fever, chills, headaches, myalgia, malaise, anorexia, dry cough, sore throat, nasal congestion/discharge

Question 15

length of systemic system persistance

Answer 15

3 days, typical duration of fever

Question 16

pulmonary complications of influenza

Answer 16

pneumonia, croup, COPD

Question 17

non-pulmonary complications of influenza

Answer 17

myositis, cardiac (toxic shock), guillain-barre (influenza A), transverse myelitis, encephalitis, Reye syndrome (aspirin in children)

Question 18

real-time PCR test

Answer 18

most sensitive and specific, but low availability and long wait for results

Question 19

RA rapid antigen detection

Answer 19

used in ER, takes 10-20 minutes, but only has a sensitivity around 60%, so you get a lot of false negatives; if you get a negative, you should probably double check with RA

Question 20

M2 blockers

Answer 20

work by blocking uncaring by amantadine

Question 21

neuraminidase inhibitors

Answer 21

prevent the release of the virus through exocytosis by oseltamivir (tamiflu) and zanamivir

Question 22

early antiviral treatment can

Answer 22

shorten illness/fever duration, reduce death, shorten hospitalization in children

Question 23

when to start antiviral treatment

Answer 23

within 48 hours of symptom onset

Question 24

who do you give antiviral treatment as early as possible to when influenza is suspected

Answer 24

hospitalized patients, severely ill patients at high risk for complications, complicated/progressive comorbidities

Question 25

what drugs are the M2 blockers

Answer 25

rimantadine and amantadine

Question 26

what drugs are the neuraminidase inhibitors

Answer 26

oseltamivir, zanamavir, peramivir

Question 27

rimantidine

Answer 27

blocks viral uncaring by blocking M2 proton channel, oral administration, treats influenza A, some GI intolerance and CNS effects

Question 28

amantidine

Answer 28

blocks viral uncaring by blocking M2 proton channel, administered orally, treats influenza A

Question 29

what virus strain do M2 blockers prevent

Answer 29

influenza A

Question 30

Oseltamivir

Answer 30

tamiflu, pro-drug activated in gut and liver, inhibit neuraminidase, administered orally, treats influenza A and B, well-tolerated with some nausea and vomiting

Question 31

Zanamivir

Answer 31

relenza, inhaled drug, inhibits neuraminidase, treats influenza A and B, bronchospasms occur in asthmatics, nausea, and diarrhea

Question 32

Peramivir

Answer 32

Rapivab, IV admin, inhbiits neuraminidase, treats influenza A and B, causes diarrhea

Question 33

when to use influenza prophylaxis

Answer 33

close contact with person who has confirmed/probably/suspected influenza IF high risk for complication, IF <48 hours since last contact, and IF contact within 24 hours of infections period (fever subsiding)

Question 34

definition of “close contact”

Answer 34

cared for/lived with person with flu, high likelihood of contact with large droplets/body fluids, talked fact-to-face, intubated them, etc.

Question 35

which populations qualify for the high dose vaccine

Answer 35

adults >65, kids 6-8 months require 2 doses if it’s their first vaccine, and high risk individuals i.e. HIV positive, will get high-dose vaccine

Question 36

common cold viruses

Answer 36

rhinovirus and respiratory syncytial virus

Question 37

RSV is significant because

Answer 37

it is the most common cause of death from respiratory illness in young children, and the leading cause of death from respiratory illness in those >65

Question 38

if the vaccine matches the circulating strain well, what’s your risk reduction for developing flu that will lead to a dr. appointment

Answer 38

50% risk reduction

Question 39

relative measure of effect

Answer 39

1-odds ratio x 100, so what are the odds those with the flu were vaccinated/what are the odds those without the flu were vaccinated
1-that x 100

Question 40

number needed to treat

Answer 40

well matched: 37, not well matched: 77

Question 41

hemagglutanin

Answer 41

binds sialic acid and promotes viral entry into the host cell

Question 42

neuraminidase

Answer 42

promotes progeny virion release