whcih influenza is responsible for pandemics
A
which of the single stranded family of RNA viruses causes influenze
orthomyxoviridae
how is influenza spread
resp droplets from coughing and sneezing
touching nose and mouth after touching something with influenza virus
when is influenza transmittable
1 day before symptoms develop and 5-10 days after becoming sick
incubation period for influenza
1-4 days
what is the most common subtype of inflenza detected
influenza A H3N2
common clinical presentation of influenza
abrupt onset of..... high fever muscl epain headache non productive cough malaise sore throat rhinitis
when do you see resolution of symptoms
resolves in 1 week
cough and malaise may persist for more than 2 weeks
diagnosis difficult based on symptoms alone what can help confirm that it is influenza
respiratory symptoms or fever during influenza season
fever in influenza or cold?
rare in common cold
high in influenza
headache in i or c?
headache frequently in influenza and rarely in cold
aches, pains or wekness in i or c?
influenza has severe aches and pain and weakness that can last months
cold maybe has some slight aches and pains
bedridden with i or c?
influenza can be bedridden for 5-10 days
not bedridden with a cold
runny stuffy nose or sneezing in i or c?
much more common in a cold but can happen in influenza
chest discomfort in i or c?
usually have chest pain in influenza
sometimes in cold but much more mild
complications that can occur due to influenza
respiratory failure, especially if the patient has chronic conditions (exacerbation)
viral pneumonitis
pneumonia - secondayr bacterial infection
dehydration
worsening of concurent medical conditions
viral myocardidis - rare
acute coronary syndrome
complications of a common cold
congestion
sinus or ear infection
prevention of influenza
vaccine
frequent hand washign
cover cough
prevention of the common cold
frequent hand washing
cover cough
causes of secondary bacterial pneumonia that can occur in severe influenzal illness
staph aureus
strep pneumoniae
h inflenzae
other gram negative bacilli
where do you take samples from to test for influenza
nasopharyngeal or throat swab
nasal wash
nasal aspirate
blood for antibodies
how long does it take for viral culture to produce results
3-10 days
during outbreaks what should you include in the samples and why
culture so influenza subtypes can be determined and for surveillance for new strains that may need to be included in next years influenza vaccine
what are fapid influenza diagnostic tests
immunoassays that can identify the presences of influenza A or B viral nucleoprotein antigens in resp specimines and display the result in a qualitative way (positive or negative)
advantages of rapid influenza tests
produce quick result in 15 min or less
simple to perform
some approved for office/bedside use
disadvantages of rapid influenza tests
sensitivity
false negatives common esp when influenza acivity is high
false positive also occur when activity is low
do not provide info on influenza A subtype or specific strain
what is serological testin
testing serum samples for influenza antibody to diagnose recent infection
how is serological testing done
collect one sample within the first week of illness and the second 2-4 weeks later
what do the results of serological testing tell you
if antibody levels are higher in the second sample than in the first, likely that influenza virus was present
what is the role of serological testing
seroprevalence studies
surveillance
osteltamivir path thought the body
converted to active metabolis by hepatic esterases
cleared by glomerular filtration and tubular secretion by an anionic transporter system
why should you reduce the dose of oseltamivir in renal impairment
clearance by the kidney
side effects of osteltamivir
NV
diarrhea
take with food
why is zanamivirs use limited
not orally bioavailable
administered by inhalation via a dry powder inhaler
not much is absorbed systemically so distribution of the drug to extrapulmonary sites is minimal
dosage adjustment of zanamivir for people with impaired renal or hepatic function
not metabolized or secreted renally so no dosage adjustment is suggested
when must an antiviral e administered to reduce the duration of uncomplicated influenza by one day and reduce the risk of complication in the severly ill
2 days
who should antiviral treatment be offered to
ppl at higher risk for complications
<2 - >65
chronic pulmonary, cardiovascular, renal, hepatic, hematological, metabolic, neurological disorders
immunosuppression, HIV
pregnant or 2 weeks post partum
under 19 recieveing long term aspirin therapy
first nation, inuit, metis
morbidly obeses
residents of nursing homes and other chronic care facilities
is there any resistance to oseltamivir or zanamivir
no
why are adamantanes no longer used
resistance to it
what happened when the 2 antivirals were combined in comparison to just oseltamivir
decreased efficacy
result of the combo product vs just zanamivir
increased efficacy
is an increased dose of oseltamivir recommended
may have faster eradication but does not decrease mortality
increases chance of renal failure, not worth it
when is influenza season
october to may
what age can you start getting the vaccine
over 6 months
how long fdoes ti take to develop immunity after recieving the qaudrivalent flu vaccine
2 weeks***
the current vaccines do not contain an adjuvant what is that
substance that boosts an individuals immune response to the vaccine
what does the vaccin result in the production of
circulating iGg antibodies to the viral hemagglutinin and neuraminidase
cytotoxic T lymphocyte response
what does the antibody response after vaccination depend on
age
prior and subsequent exposure to antigens
immunodeificiency states
what do you have to get the flur shot every year
viruses change over time
antigenically drifted strains so have to change the antigenic components of the vaccine each year
does administering a second dose of influenza vaccin result in an antibody boost
no
who should not be vaccinated***
previous anaphylactic shock to any element
IgE hypersensitivity to eggs
currently experiencing a high fever
serious acute febrile illness until symptoms have lessened
can give if non serious febrile illness
adverse reactions to vaccination
mild symptoms may last 1-2 days
soreness, redness, swelling where injection given
fever in children
drug interaction swith vaccine
can inhibit the clearance of warfarin and theophylline but no adverse effects