respiratory viruses

Question 1

what are the types of influenza and which has an animal reservoir?

Answer 1

A,B,C

A is carried by birds (waterfowl)

Question 2

influenza family, genome, virion and imp. proteins

Answer 2

orthomyxovirida
8-segmented -ssRNA
enveloped
hemagglutinin prot helps attach and neuraminidase prot helps viral release

Question 3

how is influenza identified?

Answer 3

based on hemagglutiin and neuraminidase serotypes

these are basis of transmission ability

Question 4

how does hemagglutinin protein work?

Answer 4

as it goes from neutral to acidic pH there’s a conformational change that allows membrane fusion and the core can enter the cell.

Question 5

how is influenza an exception in terms of genome?!?

Answer 5

it’s -ssRNA but it enters the nucleus for replication
as neucleocapsid is formed it migrates to cell surface and uses neuramididase to cleave connections to the cell and bud out

Question 6

what’s the main way influenza is transmitted?

Answer 6

aerosol, large and small droplets (esp. small)

Question 7

disease progression for influenza

Answer 7

1-4 days incubabion
contagious day before sympt onset to 5 days later
infection length depends on previous exposure

Question 8

influenza disease traits and complications

Answer 8

interpandemic = seasonal
current strains = H3N1 and H1N1
people usually pass it to 1 or 2 others
complications = viral and bacterial pneumonia reye syndrome and otitis media

Question 9

vaccine used for influenza

Answer 9

live attenuated mixed with wild type

usually contains H3N1, H1N1 and type B

Question 10

antivirals for influenza

Answer 10

amantidine and rimantidine block M2 prot from letting influenza escape endosome
tamiflu - targets neurimididase prot. that lets virus bud

Question 11

influenza pandemics

Answer 11

spanish flu - H1N1 caused cytokine storm in healthy adults
asian flu - new serotype H2N2
hong kong - H3N2
H1N1 - recently

Question 12

why are avian H5 and H7 such highly pathogenic strains? and why does this worry us?

Answer 12

effect more than epithelial cells, can effect any cell

avian strains can mutate to affect people

Question 13

how are adenoviruses classified?

what causes respiratory infection and which cause acute respiratory disease?

Answer 13

serotype as well
respiratory infections: 1,2,5,6
acute respiratory disease: 4,7,21

Question 14

adenovirus genome virion and shape

Answer 14

dsDNA
non-enveloped
hexagonal

Question 15

how do adenoviruses enter a cell?

Answer 15

enter via coxsackle-adenovirus receptor
pH triggers capsid disassembly
moves to nucleus

Question 16

how do adenoviruses replicate and spread?!?

Answer 16

gene expression in 3 phases immediate early E1 phase causes cell replication
early phase prevents apoptosis by blocking TNF
late is take over of cellular mRNA by blocking IFN from translating cellular proteins
leaves cell after it dies and lysises

Question 17

what do adenovirus respiratory diseases look like?

Answer 17

common cold - causes respiratory infection

acute respiratory disease causes more severe pneumonia

Question 18

how is adenovirus used in research?

Answer 18

as vector for genetherapy

Question 19

what do we know as common cold? how do you treat it?

Answer 19

rhinovirus, no vaccine (too many serotypes) no antivirals

Question 20

biology traits of rhinovirus

Answer 20

surface proteins vary/mutate a lot 
humans are only carriers
picornavirus family 
\+ssRNA
non-enveloped