Viral infection Flashcards
what 4 ways can virions be transmitted?
1) airborne
2) contact or faeces
3) contaminated water
4) blood
what do you call virions that spread through the blood?
viremia
how long does herpes simplex take to replicate in order to show symptoms?
2-8 days
how long does hepatitis A take to replicate in order to show symptoms?
15-40 days
what is incubation?
time the virus takes to replicate in order to show symptoms
what are the many effects or interactions (4) that a virus may have with the host?
the virus may be:
1) oncogenic
2) lytic or acute
3) persistent or chronic
4) latent
what is an acute or lytic virus?
enters the cell, replicates and destroys the cells to release virions
what is an oncogenic virus?
it causes cancer
what is a persistent or chronic virus?
a virus that remains constant
what is a latent virus?
a virus that hides in the cell and is considered “silent”
what is cytopathogenesis?
mechanisms by which viruses alter host on a cellular level.
how does herpes simplex virus alter host on cellular level?
inhibits cellular protein synthesis
how does herpesvirus modify host on a cellular level?
inhibition and degradation of cellular DNA
what is syncytia?
giant multi-nucleated cell formed by fusion of a virally infected cell with a new cell.
what are inclusion bodies?
it is an intracellular compartment composed of manipulated membrane and new viral components that stains densely.
what virus causes this inclusion body refered to as nigri body?
rabies
what virus causes this inclusion body refered to as owl eye?
CMV
a nigri body by rabies is what?
intracytoplasmic inclusion
an owl eye inclusion by CMV is what type of inclusion?
a basophilic intranuclear inclusion with a halo
what virus causes a Cowdry type A inclusion?
Herpes simplex virus or VZV (varicella)
what type of inclusion body is the Cowdry type A?
a eosinophilic intranuclear inclusion
what virus causes this inclusion body?
Adenovirus pneumonia
what type of inclusion body does the adenovirus pneumonia cause?
basophilic intranuclear
what happens to the cell when poliovirus infects the cell?
it inhibits protein synthesis
what happens to the cell when herpes simplex virus infects a cell?
it cuases inhibition of protein synthesis
what will all enveloped viruses cause when they infect a cell?
they will alter the cell membrane through:
1) glycoprotein insertion
2) Sycncytia formation
3) change the permeability
what are the enveloped viruses?
1) herpes simplex virus
2) varicella (chicken pox; VZV)
3) HIV
4) paramixovirus
5) togavirus
6) herpesvirus
what viruses will cause the body to be immunosuppressed?
HIV
cytomegalovirus
measles
influenza
chicken pox or VZV will cause what inclusion body?
is it cytoplasmic or nuclear?
a guarneri inclusion body
cytoplasmic
what 2 viruses create owls eye inclusion bodies?
is this inclusion body nuclear or cytoplasmic?
1) herpes simplex virus
2) chickenpox (VZV)
nuclear
what inclusion bodies does reovirus create?
acidophilic perinuclear bodies
in what ways does a virus alter a host organ and system level?
1) organ failure by killing cells
2) immune reaction to the infection through cytokines
3) can induce autoimmune disease
4) prevents organ development
what substance in the body gets released in order to control viral infection?
interferon alpha and beta
what does inteferon do to virus?
it stops translation of viral replication
how do natural killer cells kill virally infected cells?
by recognizing cells with down-regulated (missing) MHC 1
what is a transient virus infection?
it is a virus that is cleared by the immune response
what is a persistent viral infection?
the virus doesnt get cleared and the immune system keeps active
what are the 3 types of persistent viral infection?
1) chronic
2) latent
3) recurrent
what is a slow viral infection?
its a chronic persitent infection that has a long incubation period of moths to years
what is a chronic persistent viral infection?
it is a virus that is continuously present
what is a latent persistent viral infection?
a virus that has its genome present but does not produce virions
what is a recurrent persistent viral infeciton?
latent infection that reactivates and produces virions before becoming active
