1.3 Respiratory Viruses

Question 1

• family orthomyxoviridae
• ssRNA, enveloped viruses with a helical nucleocapsid
• genome of 7-8 segments
• types A, B, C, D
• HA, NA, M2

Answer 1

influenza viruses

Question 2

in influenze viruses, facilitates attachment to sialic acid rececptor

Answer 2

hemagglutinin (HA)

Question 3

in influenza virus, facilitates release of infectious virus from cells

Answer 3

neuraminidase (NA)

Question 4

in influenza virus, necessary for virus entry

Answer 4

M2 protein

Question 5

influenza pathogenesis?

Answer 5

virus deposited on the respiratory tract epithelium, attaches to and penetrates columnar epithelial cells

Question 6

normally prevents attachment of influenza virus to columnar epithelial cells?

Answer 6

specific secretory IgA antibodies against hemagglutinin, mucoproteins, and mucociliary apparatus

Question 7

key cytokine storm mediators in influenza?

Answer 7

IL-6, TNF-alpha, Interferon a/b, IL-1 a/b, IFN-gamma

Question 8

• point mutations in antigenic sites reduce or inhibit binding of neutralizing antibodies
• generally results in local epidemics
• occurs in influenza A and B

Answer 8

antigenic drift

Question 9

• a sudden, major change in the antigenic structure of HA and/or NA
• results in pandemics because the populations don’t have neutralizing antibodies against the new virus
• occurs only in influenza A

Answer 9

antigenic shift

Question 10

• two different viruses infect the same cell

- new strains emerge

Answer 10

genetic reassortment influenza

Question 11

H1N1 resembles an _____ origin virus, reappeared as Russian flu in 1977

Answer 11

avian

Question 12

in influenza immunity, which are the protective antigens of the virus?

Answer 12

HA and NA glycoproteins

Question 13

influenza vaccines are ________ and given ________, the purified virus is split with a detergent and components purified

Answer 13

inactivated, intramuscularly

Question 14

• enveloped, pleomorphic virions
• contain non-segmented, (-) ssRNA
• syncytia inducing viruses

Answer 14

paramyxoviruses

Question 15

includes measles virus, mumps, respiratory syncytial virus, metapneumovirus

Answer 15

paramyxovirus

Question 16

attachment protein of paramyxovirus and mumps?

Answer 16

HN protein

Question 17

attachment protein in measles?

Answer 17

H glycoprotein

Question 18

attachment protein in RSV?

Answer 18

G glycoprotein

Question 19

all paramyxoviruses have a ________ protein, allows syncytia to form

Answer 19

F (fusion)

Question 20

replication of paramyxovirus?

Answer 20

fusion of viral and cellular membrane through action of F protein, makes positive transcript, mRNAs translated to protein, assembly and release at plasma membrane

Question 21

paramyxoviruses cause fusion of neighboring cells, mediated by F protein of virus

Answer 21

syncytia formation

Question 22

measles rash caused by a ______ response against infected endothelial cells

Answer 22

T cell

Question 23

-measles virus infects cells of the ______ tract, then spreads ________

Answer 23

respiratory tract, systematically

Question 24

essential to control infection in measles, antibody is not sufficient

Answer 24

cell mediated immunity

Question 25

requirements for measles?

Answer 25

cough, coryza, conjunctivitis, temp >101, maculopapular rash >3 days

Question 26

most common complication of measles?

Answer 26

acute otitis media

Question 27

slowly progressing neurodegenerative disease post-measles infection, get cognitive change then motor dysfunction followed by vegetative state

Answer 27

subacute sclerosing panencaphalitis

Question 28

• acute, benign viral parotitis, can cause encephalitis as well as orchitis
• only one serotype, man is only reservoir
• cell mediated immunity essential, antibody not sufficient to prevent virus spread
• immunity is lifelong

Answer 28

mumps virus

Question 29

• major cause of lower respiratory tract infections and hospital visits during infancy and childhood
• belongs to pneumovirus and paramyxovirus family

Answer 29

respiratory syncytial virus

Question 30

at risk of severe infection with RSV?

Answer 30

• infants with congenital heart disease
• underlying pulmonary disease such as bronchopulmonary dysplasia
• immunosuppressed or immunocompromised

Question 31

• ssRNA virus, enveloped, pleomorphic

- 5 serotypes, no antiviral therapy

Answer 31

parainfluenza virus

Question 32

• an enveloped RNA virus, member of the family togaviridae

- RNA of positive polarity, only one serotype, humans the only reservoir

Answer 32

rubella virus

Question 33

in non immune mothers are infected in the first trimester, 80% of neonates affected

Answer 33

rubella virus

Question 34

• initial site of infection the upper respiratory tract, then viremia
• immunologic basis for rash
• patient infectious from 1 week before rash to 1 week after
• maculopapular rash

Answer 34

rubella

Question 35

• infection of fetus may affect all organs, leading to fetal death or premature delivery
• 85% affected if during first trimester
• triad of cataracts, heart defects, sensorineural loss

Answer 35

congenital rubella syndrome

Question 36

triad of symptoms in congenital rubella syndrome?

Answer 36

cataracts, heart defects, sensorineural deafness

Question 37

what type of vaccine is MMR?

Answer 37

live attenuated

Question 38

two viruses responsible for the common cold?

Answer 38

rhinovirus and coronavirus

Question 39

• small non-enveloped ssRNA virus
• belong to picornavirus family
• acid labile, greater than 110 serotypes

Answer 39

rhinoviruses

Question 40

ssRNA virus, enveloped, pleomorphic

-can causes SARS and MERS

Answer 40

coronavirus