Influenza Flashcards
Scariest side effect of 1976 Swine flu vaccine
guillon-barre
What is Influenza A
Infects humans and animals
causes pandemics
What is Influenza B
Infects only humans
NO pandemics
Two surface proteins and # of them
Hemaglutinin (H1-H15)
Neurominidase (N1-N10)
Influenza A flu types are further naems according to…
Where they were first ideantified, their lineage year isolated
Minor changes in Influenza antigen proteins
So what?
Drift
Keeps you susceptible from year to year
Major changes in Influenza antigen proteins
Shift
Unique setup of influenza genome
RNA
Each gene of influenza is encoded on a separate strand
When can antigen shift happen
Viruses of two kinds infect the same cell and pull the genetic switcharoo
Animal most responsible for the origin/spread of influenza in all other animals
Ducks
Fist major bird flu
Spanish Flu
1918
Asian Flu (1957) was comprised of….
H1N1 + H2N2
As time went on its new genes added on to the next big thing
Typically how many strains can cause pandemic at at a time
One
What’s the deal with H1N1 Russian Flu
Identical to Russian Flu
Possibly caused by a lab release
How is influenza transmitted?
Large droplets (sneezing/coughing)
Close contact
Not so commonly spread on contaminated surfaces
Not carried in pork/chicken meet
Clinical effects of influenza
Fever, Headache, Myalgia, and Fatigue
Cough, Sore Throat, Nasal Discharge to follow
Fatigue/Weakness may last for week
Symptoms that are mistakenly associated with flu
Nausea, Vomiting, Diarrhea
Complications of Influenza
Viral/Bacterial Pneumonias Myositis and Rhabdomyolysis MI Encephalitis/Encephalopathy (Rare) Reye's Syndrome (From taking too much Aspirin)
Most common post-flu bacterial pneumonias
Strep pneumo
S. aureus
Unique things about Spanish Flu (1918)
- Started typical, then worsened several days later due to bacterial secondary infection.
- High Dose Aspirin
Things unique to Bird Flu (H5N1)
Mostly kids and adults
Very high mortality rates (60%)
Usually respiratory, but some diarrhea+neuro components
Transmission risk of Bird Flu (H5N1)
Very low person to person transmission
Things unique to H7N9
China 2013
Elderly severe respiratory stress
Pretty much gone now
Things unique to Variant H3N2 influenza
Indiana
Close contact with pigs
H1N1 + and a pig H3N2 genes combined
No sustained transmission, mid disease
Average Mortality. Mild Year? Severe year/pandemic?
Mild – 3,000 (mostly elderly)
Severe – 45,000 (children)
How to diagnose influenza?
BEST TEST – PCR, sensitive and fast, but expensive
Rapid antigen tests
*Viral culture (gold standard, but takes time)
Serology is pretty useless
Treatment for influenza?
None are very good
Old school – Amantadine + Rimantadine (useless now)
Now – Neuraminidase inhibitors
Name two neurominidase inhibitors
Oseltamivir, Sanamivir
When do you need to provide treatment to help flu?
Within 48 hours of symptom onset
Could reduce symptoms by 1-2 days
MOA for Zanamivir?
Oral Inhalation
IV available
Why new vaccines every year?
Antigenic drift in predominant circulating strain
Why do they make the guess on the flu vaccine so early?
It takes 9 months to mass produce the vaccine
They are grown in eggs. One egg makes one shot.
How does the making a vaccine in an egg thing work?
Eggs with virus are purified and virus is inactivated with formaldehyde
Currently further purified to have only HA and N antigens (split vaccine) to decrease side effects
Side effects of Flu vaccine
Not Flu
Possibly Guillain-Barre
How do you vaccine the egg-allergic
Cell culture based vaccine
Entirely recombinant vaccine
Live attenuated vaccine for those under 50
Why get the live, attenuated virus vaccine?
May possibly give better protection
Are vaccines very effective?
Mostly in kids
Not so much for those over 65
Vaccines are thought to provide only _____ immunity
Non-sterilizing
Contents of current vaccines
Either two A strains and 1 B strain or two of each
Contents of 2015 vaccine
H3N2 strain plus 1-2 B strains
Effectiveness of 2013-14 vaccine?
2014-2015?
51%
23%
