Influenza Flashcards
What is influenza?
acute, febrile respiratory disease (NOT GI upset and NOT mild respiratory illness)
Influenza virus is an ____ virus with a segmented genome.
enveloped ssRNA
The influenza virus genome is made up of _____.
8 pieces of ssRNA
Two of the best characterized viral proteins are the ____ and _____ glycoproteins, which identify the subtype of influenza based on their combination in the viral coat.
hemagglutinin (H); neuraminidase (N)
There are 3 types of influenza viruses: ___ and ____, which circulate in the pop. every year, and ____ that causes a mild/clinically insignificant illness.
A and B; C
How do repeated influenza epidemics persist?
type A and B viruses undergo constant and rapid change due to antigenic drift
When does antigenic drift occur? Why?
only after a strain has become established in humans; it has adapted to the host Abs
Influenza virus is an RNA virus with a ____ genome.
segmented
What is antigenic drift?
gradual change in the virus via mutations, substitutions, or deletions in aas that make up the H or N surface antigens
What is antigenic shift?
a completely novel hemagglutinin or neuraminidase gene segment is introduced
Where does the new gene segment in antigenic shift come from?
other host species (birds or swine)
How is influenza transmitted?
respiratory route, contamination of hands and inanimate objects
What is the incubation period for influenza?
1-3 days
What are the s/s of influenza in adolescents and adults?
acute onset fever, chills, myalgias, headache, cough
What are the s/s of influenza in a neonate?
resembles bacterial sepsis, including lethargy, decreased eating, mottling
What are the s/s of influenza in toddlers?
GI symptoms (nausea, vomiting, diarrhea), fever, anorexia, URI, croup, bronchitis, convulsions
What are the 2 general treatments for influenza?
- matrix protein inhibitors
2. neuraminidase inhibitors
What are the 2 matrix protein inhibitors and what do they target?
- amantadine
- rimantadine
subtype A viruses
What are the 3 neuraminidase inhibitors and what do they target?
- oseltamivir (Tamiflu)
- Zanamivir (Relenza)
- Peramivir (Rapivab)- IV
subtype A and B viruses
What are the 2 types of seasonal flu vaccines?
- inactivated influenza vaccine (IIV))
2. live attenuated influenza vaccine (LAIV)
What is the inactivated influenza vaccine?
injectable, killed vaccine for 6mos+; trivalent and quadrivalent
What is the live attenuated influenza vaccine?
intranasal live attenuate vaccine for 2-49yo; quadrivalent
What is swine influenza/pandemic H1N1?
the 2009/10 swine influenza virus created from reassortment; mostly affected those under 24yo
What is avian influenza?
infectious influenza A in birds- asymptomatic but shed in huge amounts in feces = storage reservoir
Avian viruses bind in an alpha-2, 3-linkage, whereas human viruses bind in an _____.
alpha-2,6-linkage
Why doesn’t avian flu usually infect humans?
it doesn’t have the correct receptor
Name 2 ways influenza pandemics could emerge.
- avian to human transfer
2. reassortment of human strains to avian strains via pigs
What are the 3 criteria for a pandemic?
- emergence of a new flu subtype
- virus infects humans and causes serious illness
- virus is transmitted from human to human w/o interruption
Avian viruses bind in an_____, whereas human viruses bind in an alpha-2,6-linkage.
alpha-2, 3-linkage
