Influenza Flashcards
Who is at risk for serious complications?
-65 yrs and older
-Nursing home residents
-persons with chronic diseases
-pregnant women
-infants
What kind of diseases are Influenza?
Respiratory Viruses
How is Influenza transmitted
Through contact with respiratory droplets from coughing and sneezing
What is an Incubation period?
How long before you look and feel ill
What is the incubation period of Influenza?
1-5 days from exposure to symptoms
What is Communicabiltiy?
How long before you are contagious
What is the communicability period of Influenza?
1-2 days prior to symptoms and 4-5 days after symptoms
What is peak time for the flu in North America?
December through March
What are the symptoms of Influenza?
A rapid onset of….
-fever and chills
-body aches, headaches, sore throat
-non-productive cough ; runny nose
True or false:
Diarrhea and Vomiting are common with Influenza
False- they are rare symptoms
True or False:
Virus in the bloodstream is common
False
What does it mean if Influenza is Group A
-can do both antigenic shift & drift
-epidemics/pandemics, risk to all ages
-infects humans AND animals
What does it mean if Influenza is Group B
-can only do antigenic drift
-risk to children and aged
-slow, mutational change through the year
-ONLY infects humans
What is Group B Influenza also known as?
The seasonal flu
What does it mean if Influenza is Group C
-mild respiratory tract infections
-no epidemics
What structures are found in the Influenza virus?
-segmented ssRNA genome
-helical capsid
-Envelope with H-spikes & N-spikes
-matrix proteins
-Virus RNA polymerase
What do helical capsids do in the virus structure?
protect nucleic acid genome
What do h-spikes do in the virus structure?
used to get into host cells
What do n-spikes do in the virus structure?
used to get out of host cells
What do matrix proteins do in the virus structure?
allows virus to associate its capsid with the envelope
What do Virus RNA polymerase do in the virus structure?
replicates negative viral strand
What are Group-Specific Antigens?
-capsid distinguishes Groups A,B,C
-Antibody vs capsid does NOT neutralize virus
What are Type-Specific Antigens?
-H and N proteins
-Antibody vs H neutralizes virus
What are factors of antigenic drift?
-occurs in H and N
-MINOR change in antigens
-Associated with Group B
-mutations
What are factors of antigenic shift?
-occurs in H and N
-MAJOR changes in antigens
-Associated with Group A
-Flu’s segmented genome can re-assort
-Re-assort new H’s or new combos of H and N
-animal flu viruses provide new segments
What is the danger if antigenic shift occurs?
A pandemic may occur if…
-efficient & sustained human-human transmission
-widespread mobility & mortality worldwide
-high proportion of deaths among young adults
What are the usual avian influenza A viruses?
H1 - H16
N1 - N9
What are the usual human influenza A viruses?
H1 - H3
True or False:
Different Flu Substrates can re-assort in a shared host
True
What makes H5N1 so virulent?
it elicits an exaggerated cytokine response “storm” that can cause the body to kill itself, rather than the virus being the cause of death
