principles of viral infection Flashcards
viruses are obligate int…
viruses are obligate intracellular parasites
do virus contain dna or rna
can have either
what are the three types of virus structure
capsids that are either icosahedral, helical, complex
why are the viral surface proteins so importnant
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
what is tropism
the source of cells that the virus can get into
is the clinical manifestations of disease solely due to the viral infection
no it is also due to the immunological response
what is incubation time
time between exposure and onset of specific clinical signs
what is prodrome
period during incubation time before specific clinical sign, where patient will have non specific constitutional symptoms of illness malaise, fever
what is difference between superficial and systemic infection
superficial is local, upper respiratory tract, systemic can be ebola chicken pox spread by lymph vessels
what is acute infection
comes on at once and clears away
what is persistent infection which is latent
you recover but microorganism persists and can be reactivated, chronic is when you have continued production of pathogen which evades immune system
what is direct detection (diagnostic virology)
looks for the presence of the virus to fdiagnose
what is indirect detection (diagnostic virology)
looks at the immune response for virus to deduce it is there
name some direct detection methods of viruses
viral culture, electron microscopy, antigen detection, nucleic acid amplification technology
name some indirect methods of detection for viruses
blood serum or plasma examine for antibodies against pathogen
cells in viral culture that support viral replication are called?
permissive
what can you see in a vrial culture of cells positive for a virus
giant cells, rounding , inclusion bodies these all fall under the term cytopathic effects
how do you detect virus with rna using pcr
first use reverse transcriptase to form cdna then you can now do pcr
how do serological techniques detecting viruses work (ELISA)
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
igm serological diagnosis is used to diagnose..
acute infections
acute infection can also be demonstrated by seroconversion which involves
appearance of different antibody class
what are main ways to control infection
public health, immunization and antiviral therapies
what is the challenge effecting antiviral drugs
they have to try not to effect normal cells
what do antiviral agents commonly target
attachment and entry, nucleic acid synthesis, and assembly and budding
polymerase inhibitors are antiviral drugs what do they prevent
they prevent inhibit nucleic acid synthesis
what are the two actions of polymerase inhibitors
by nucleic acid target or by targeting chemical structure
what is difference between a nucleoside and a nucleotide
nucleotide has phosphate nucleoside does not
name nucleoside analogues
aciclovir and ganciclovir
name nucleotide analogue
cidofovir treates herpes
name non nucleoside dna polymerase inhibitor
foscarnet for cmv
name some viral resistance strategies to antivirals
spontaeneous mutations, rna polymerase in virus is error prone,
