DD- Virology of influenza Flashcards by MO ROUTH

An infectious disease caused by the influenza virus. The most common symptoms include: a high fever, runny nose, sore throat, muscle pains, headache, coughing, and feeling tired.

The flu

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Persons _________of age account for more than 90% of deaths from the Flu

> 65 years

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Influenza cases peak during the ______season

winter/spring

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Influenza virus is an______virus with a segmented genome

RNA

Its genome is made up of 8 different pieces of single-stranded RNA, which encode several different viral proteins

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Surrounding the core of influenza is a lipid envelope, with a lining of ______on the inner side of the envelope.

matrix protein

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Two of the best characterized_________are the hemagglutinin (H) and neuraminidase (N) glycoproteins.

flu viral proteins

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Influenza viral subtypes are identified by the combination of________on the viral coat (e.g. H1N1, H3N2 etc).

H and N proteins

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There are 3 types of influenza virus.

Type A and Type B strains circulate in the population every year.

Type C strains cause__________

mild or clinically-insignificant illness

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Type A strains are the cause of both epidemics and pandemics. Type A strains can infect__________

other animals

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Two of the best characterized flu viral proteins are the_________ and neuraminidase (N) glycoproteins.

hemagglutinin (H)

*Both hemagglutinin and neuraminidase are surface proteins.

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Hemagglutinin (HA) is involved in

cell entry

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Neuraminidase (NA) is involved in:

cell escape

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There are 3 types of influenza virus.

Type A and Type B strains_________

Type C strains cause mild or clinically-insignificant illness

circulate in the population every year.

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Two of the best characterized flu viral proteins are the hemagglutinin (H) and __________

neuraminidase (N) glycoproteins.

*Both hemagglutinin and neuraminidase are surface proteins.

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Influenza binds _______ to enter cell

sialic acid

Common in lungs

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Potentially severe illness:

Epidemics and pandemics
Rapidly changing
Birds, swine, dogs, cats, horses, seals, whales, humans

Type A Influenza

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RNA virus are sloppy when they replicate leading to many:

mutations

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Usually less severe illness

Epidemics, no pandemics
More uniform
Humans

Type B Influenza

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Type A Name example:

A/California/7/2009 (H1N1)

a- Virus type
California- Geographic origin
7- Strain number
2009- year of isolation 
(H1N1)- subtype

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Antigenic Drift

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a mechanism for variation in viruses that involves the accumulation of mutations within the genes that code for antibody-binding sites.

Antigenic Drift in flu virus can affect________ to stop AB binding

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Hemagglutinin

Antigenic Shift is in _____ only

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Type A

Major change, new subtype
Caused by exchange of gene segments
May result in pandemic

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Antigenic SHIFT

Minor change, same subtype
Caused by point mutations in gene
May result in epidemic

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Antigenic DRIFT

Transmission of Influenza

Droplet spread- Small particle aerosols

Influenza is transmitted primarily by the ________route

respiratory

Signs and symptoms of influenza in adolescents and adults

acute onset of fever, chills, myalgias, headache and cough

presentation tends to resemble that of bacterial sepsis, including lethargy, decreased eating and mottling

flu in neonates

tend to present with gastrointestinal symptoms (NVD); fever; anorexia; and various respiratory syndromes, including (croup), bronchiolitis, bronchitis and febrile convulsions

flu in Infants and toddlers

Major groups of Flu Rx

Matrix protein inhibitors | Neuraminidase Inhibitors

Matrix protein inhibitors: Amantadine Rimantadine Only work on Influenza______subtypes

Type A

Neuraminidase Inhibitors: Oseltamivir Zanamivir Peramivir (just approved 12/14) Work on Influenza__________subtypes

types A and B

Matrix protein inhibitors | Work on?

M2 protein a proton-selective ion channel protein, integral in the viral envelope of the influenza A virus.

Neuraminidase Inhibitors | works on?

preventing its reproduction by budding from the host cell. block the neuraminidase enzyme

an influenza that reassorts in swine and then infects humans

Swine Influenza ex: Pandemic H1N1

__________ were at exceptionally high risk for hospitalization and death if infected with Pandemic H1N1 (or any influenza)

Pregnant women

Infectious disease of birds caused by type A Influenza virus

Avian Influenza

There are 2 types of licensed seasonal influenza vaccines

iInactivated influenza vaccine (IIV) Live attenuated influenza vaccine (LAIV)

this vaccine is an injectable, killed vaccine; licensed for all individuals 6 months of age and older. There are both trivalent and quadrivalent IIVs approved and available. The quadrivalent is newer, but it will likely completely replace all trivalent vaccines. The additional strain is a second B virus.

Inactivated influenza vaccine (IIV)

Both influenza vaccines contain the same 3 strains of influenza and the ________ vaccines contain the same second B strain.

quadrivalent

this is delivered intranasally via a small, needle-free syringe that delivers a fine mist into the nose; licensed for healthy persons 2 yrs through 49 years of age. This contains the same influenza strains as IIV, however, it is only quadrivalent. An additional strain is a second B virus.

Live attenuated influenza vaccine (LAIV) this is a live, attenuated (weakened strain) vaccine;

3 conditions must be met to declare a pandemic

1) Emergence of a new influenza virus subtype 2) Virus must infect humans and cause serious illness 3) Virus must have sustained transmission and spread easily among humans

Both inactivated and live vaccines are reformulated annually to provide the best protection possible for what strains are _________ to be circulating during the next season

anticipated

Intramuscular or intradermal Trivalent and quadrivalent, moving toward all quadrivalent Killed virus Standard-dose and high-dose (HD for adults 65 and older)

Inactivated Vaccine (IIV)

Intranasal Quadrivalent Live

Live attenuated influenza vaccine (LAIV) (cold adapted, attenuated influenza vaccine)

50-70% effective among healthy persons <65 in well-matched years 30%-40% effective among frail elderly Greater efficacy for prevention of hospitalization and death

Inactivated Vaccine (IIV)

Temperature-sensitive (do not replicate efficiently in lower airways) Cold-adapted (replicate efficiently in upper airway) Indicated for healthy 2-49 year olds

Live Attenuated Influenza Vaccine (LAIV)

Influenza Vaccine is Recommended for:

Everyone >6 months unless there is a contraindication to vaccination

DD- Virology of influenza Flashcards

(48 cards)