Influenza

Question 1

what does the haemagglutinin surface protein facilitate?

Answer 1

entry and attachment to the host cell

Question 2

what does the neuroamides surface proteins enable?

Answer 2

new virion to be released from host cells

Question 3

what is antigenic shift?

Answer 3

abrupt major change in the virus resulting in new H/N combinations.
there is reassortement of virus gene segment or two (or more) strains combining

Question 4

does antigenic shift allow the strain to jump between species?

Answer 4

yes

Question 5

what viral changes lead to pandemics?

Answer 5

antigenic shifts create new antigenic properties leading to pandemics

Question 6

what is antigenic drift?

Answer 6

this occurs continually all the time. there are small ongoing mutations in the genes coding for antibody binding sites

Question 7

what can antigenic drift cause?

Answer 7

> the host will eventually not be able to combat the virus
worse than normal endemics
vaccine mismatch

Question 8

how long does virus shedding occur?

Answer 8

first 4 days of the illness (longer in the immunocompromised or children)

Question 9

how long will the virus survive in a non-porous surface?

Answer 9

24-48 hours

Question 10

how long will a virus survive on a porous surface?

Answer 10

8-12 hours

Question 11

what are the requirements for a pandemic?

Answer 11

> new pathogenicity
new virus (susceptible population)
efficient person to person transmission

Question 12

how will influenza present?

Answer 12

> FEVER
> COUGH
> ONSET LAST 10 DAYS
> myalgia
> headache
> malaise
> (nausea, vomiting, diarrhoea)

Question 13

what high risk groups are there for influenza?

Answer 13

> DM
> older than 65yrs
> pregnant
> less than 6months old
> severely immunocompromised
> morbid obesity

Question 14

what common complications occur in influenza?

Answer 14

> acute bronchitis

> secondary bacterial pneumonia

Question 15

what are some less common complications of influenza?

Answer 15

> primary viral pneumonia
myositis
Gillian barre
myocarditis/pericarditis

Question 16

what are the symptoms of encephalitis lethargia?

Answer 16

> fever
> headache
> external apthalmaplegia
> lethargy
> sleep reversal

Question 17

what investigations could you carry out in a patient with suspected influenza?

Answer 17

> viral nose and throat swab (PCR)
chest x-ray
blood cultures
pulse oximetry

Question 18

when is an immunocompetent patient no longer infectious?

Answer 18

> 24hrs after last flu symptom

> when antiviral therapy is complete

Question 19

when should antiviral therapy be commenced?

Answer 19

within 48 hours of symptoms onset

Question 20

name some antiviral medication that can be used to treat influenza

Answer 20

> oseltamivir
zanamivir
peramivir
fivipravir

Question 21

what is the first line treatment in pregnancy?

Answer 21

oseltamivir

Question 22

what are some common side effects of oseltamivir?

Answer 22

> nausea
abdo. pain
vomiting
diarrhoea

Question 23

what are some uncommon side effects of oseltamivir?

Answer 23

> headache
hallucinations
rash
insomnia

Question 24

what is a side effects of inhaled zanamivir?

Answer 24

occasional bronchospasm

Question 25

true or false

the influenza vaccine is active

Answer 25

false it is inactive