Influenza Flashcards
what does the haemagglutinin surface protein facilitate?
entry and attachment to the host cell
what does the neuroamides surface proteins enable?
new virion to be released from host cells
what is antigenic shift?
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
does antigenic shift allow the strain to jump between species?
yes
what viral changes lead to pandemics?
antigenic shifts create new antigenic properties leading to pandemics
what is antigenic drift?
this occurs continually all the time. there are small ongoing mutations in the genes coding for antibody binding sites
what can antigenic drift cause?
> the host will eventually not be able to combat the virus
worse than normal endemics
vaccine mismatch
how long does virus shedding occur?
first 4 days of the illness (longer in the immunocompromised or children)
how long will the virus survive in a non-porous surface?
24-48 hours
how long will a virus survive on a porous surface?
8-12 hours
what are the requirements for a pandemic?
> new pathogenicity
new virus (susceptible population)
efficient person to person transmission
how will influenza present?
> FEVER > COUGH > ONSET LAST 10 DAYS > myalgia > headache > malaise > (nausea, vomiting, diarrhoea)
what high risk groups are there for influenza?
> DM > older than 65yrs > pregnant > less than 6months old > severely immunocompromised > morbid obesity
what common complications occur in influenza?
> acute bronchitis
> secondary bacterial pneumonia
what are some less common complications of influenza?
> primary viral pneumonia
myositis
Gillian barre
myocarditis/pericarditis
what are the symptoms of encephalitis lethargia?
> fever > headache > external apthalmaplegia > lethargy > sleep reversal
what investigations could you carry out in a patient with suspected influenza?
> viral nose and throat swab (PCR)
chest x-ray
blood cultures
pulse oximetry
when is an immunocompetent patient no longer infectious?
> 24hrs after last flu symptom
> when antiviral therapy is complete
when should antiviral therapy be commenced?
within 48 hours of symptoms onset
name some antiviral medication that can be used to treat influenza
> oseltamivir
zanamivir
peramivir
fivipravir
what is the first line treatment in pregnancy?
oseltamivir
what are some common side effects of oseltamivir?
> nausea
abdo. pain
vomiting
diarrhoea
what are some uncommon side effects of oseltamivir?
> headache
hallucinations
rash
insomnia
what is a side effects of inhaled zanamivir?
occasional bronchospasm
true or false
the influenza vaccine is active
false it is inactive
