principles of viral infection

Question 1

viruses are obligate int…

Answer 1

viruses are obligate intracellular parasites

Question 2

do virus contain dna or rna

Answer 2

can have either

Question 3

what are the three types of virus structure

Answer 3

capsids that are either icosahedral, helical, complex

Question 4

why are the viral surface proteins so importnant

Answer 4

whether or not virus has an envelope which would be derived from the plasma membrane of the cell, the outer proteins determine tropism, can be a target for antibodies and are determinants of antibody specificity

Question 5

what is tropism

Answer 5

the source of cells that the virus can get into

Question 6

is the clinical manifestations of disease solely due to the viral infection

Answer 6

no it is also due to the immunological response

Question 7

what is incubation time

Answer 7

time between exposure and onset of specific clinical signs

Question 8

what is prodrome

Answer 8

period during incubation time before specific clinical sign, where patient will have non specific constitutional symptoms of illness malaise, fever

Question 9

what is difference between superficial and systemic infection

Answer 9

superficial is local, upper respiratory tract, systemic can be ebola chicken pox spread by lymph vessels

Question 10

what is acute infection

Answer 10

comes on at once and clears away

Question 11

what is persistent infection which is latent

Answer 11

you recover but microorganism persists and can be reactivated, chronic is when you have continued production of pathogen which evades immune system

Question 12

what is direct detection (diagnostic virology)

Answer 12

looks for the presence of the virus to fdiagnose

Question 13

what is indirect detection (diagnostic virology)

Answer 13

looks at the immune response for virus to deduce it is there

Question 14

name some direct detection methods of viruses

Answer 14

viral culture, electron microscopy, antigen detection, nucleic acid amplification technology

Question 15

name some indirect methods of detection for viruses

Answer 15

blood serum or plasma examine for antibodies against pathogen

Question 16

cells in viral culture that support viral replication are called?

Answer 16

permissive

Question 17

what can you see in a vrial culture of cells positive for a virus

Answer 17

giant cells, rounding , inclusion bodies these all fall under the term cytopathic effects

Question 18

how do you detect virus with rna using pcr

Answer 18

first use reverse transcriptase to form cdna then you can now do pcr

Question 19

how do serological techniques detecting viruses work (ELISA)

Answer 19

you add viral antigen to patient serum, if present they form a complex, you need markers normally enzymes labelled human antibody which will gain colour if test is positive

Question 20

igm serological diagnosis is used to diagnose..

Answer 20

acute infections

Question 21

acute infection can also be demonstrated by seroconversion which involves

Answer 21

appearance of different antibody class

Question 22

what are main ways to control infection

Answer 22

public health, immunization and antiviral therapies

Question 23

what is the challenge effecting antiviral drugs

Answer 23

they have to try not to effect normal cells

Question 24

what do antiviral agents commonly target

Answer 24

attachment and entry, nucleic acid synthesis, and assembly and budding

Question 25

polymerase inhibitors are antiviral drugs what do they prevent

Answer 25

they prevent inhibit nucleic acid synthesis

Question 26

what are the two actions of polymerase inhibitors

Answer 26

by nucleic acid target or by targeting chemical structure

Question 27

what is difference between a nucleoside and a nucleotide

Answer 27

nucleotide has phosphate nucleoside does not

Question 28

name nucleoside analogues

Answer 28

aciclovir and ganciclovir

Question 29

name nucleotide analogue

Answer 29

cidofovir treates herpes

Question 30

name non nucleoside dna polymerase inhibitor

Answer 30

foscarnet for cmv

Question 31

name some viral resistance strategies to antivirals

Answer 31

spontaeneous mutations, rna polymerase in virus is error prone,