Enveloped Viruses: Day 3 Flashcards
What are the two important forms of enveloped DNA viruses?
Herpesvirus, Poxvirus,
What characterizes herpesviruses structurally? life cycle wise?
caspid has a protein layer overlying it called the tegument (this is underneath the envelope). these are released post infection: disarms cellular defenses.
characterized by a prolonged period of latency with occasional reactivation that is often triggered by stress
What type of virus is HSV-1 and HSV-2? What is their caspid symmetry, nucleic acid type, and site of replication?
herpes virus, enveloped DNA virus
linear dsDNA
isosahedral
In what type of cells do HSV do lytic infections? What about latent? What is different about the RNA expressed in these two cell types?
epithelial cells: lytic
have 84 genes, including DNA polymerase
some neurons: latent
only one RNA is expressed (LAT– Latency Associated Transcript)
Under stress conditions: reactivation in neurons leads to reinitiation of lytic cycle
Does latent herpes respond to drugs or immune response?
because only LAT is expressed: the enzymes that drugs target aren’t expressed, and virus can’t be recognized.
Regarding intraneuronal transport of a virus:
What is retrograde transport?
What is anterograde transport?
Retrogade: infection and replication at the portal of entry. establishes latency.
Anterograde transport: transport to a site at or near the portal of entry: during reactivation
How many herpesviruses are there?
HSV 1-8
HSV-1 and HSV-2 establish latency where?
sensory neurons
How does viral adult encephalitis occur?
HSV 1 during reactivation somehow crosses into CNS
HSV transmission, initial target, primary viremia target
transmitted through direct contact, initial to sensory neurons, primary (rare) brain
HSV 1-2 caspid symmetry, nucleic acid, site of replication
yes, isosahedral, linear dsDNA, nucleus
VZV caspid symmetry, nucleic acid, site of replication
isosahedral, linear dsDNA, nucleus
VZV transmission, initial target, primary viremia target, secondary viremia target,
aerosol, respiratory tract i sensory neurons,
primary : viral replication happens in the liver and spleen;
secondary: mononucleated cells transport virus to skin and mucus membranes, skin and mucus membranes
what is shingles?
an acute, painful inflammation of the nerve ganglia, with a skin eruption often forming a girdle around the middle of the body. It is caused by VZV
cytomegalovirus: caspid symmetry, nucleic acid, site of replication
isosahedral, linear dsDNA, nucleus
cytomegalovirus transmission, initial target, primary and seocndary viremia target
direct contact, monocytes (often in salivary glands), n/a for primary and secondary
cytomegalovirus: what percent transmits to fetus from mother with infection?
40%. this is unusual, most can’t transfer through placenta
what diseases CMV cause?
petechiaie (purple spots), liver disease, neurologic deficits
what disease causes mono?
EBV: epstei-barr virus
EBV caspid symmetry, nucleic acid, site of replication
isosahedral, linear dsDNA, nucleus
EBV transmission, initial target, primary viremia target, secondary viremia target
direct contact with saliva, sexual; initial target: oropharyngeal cells, salivary cells, B lymphocytes;
primary viremia target n/a; secondary viremia target n/a
If you do a Wright stain on EBV patients, what should you see?
atypical lymphocytes: cytotoxic suppressor T lymphocytes that are killing the infected B cells
What is the heterophile antibody test?
it’s how you can tell early (3-7 wk) diagnosis of EBV
non-specific gluttination of non-human red blood cells ?
why does the football player with mono get told to calm down and stop playing?
splenomegaly and hepatomegaly during the 5.5 - 10.5 week period
