HSV Flashcards
general characteristics of HSV?
dsDNA virus with icosaherdral capsid
mucosal epithelium infection
replication occurs in nucleus
what does HSV-1 cause?
labial lesions, fever blisters, encephalitis, keratitis
what does HSV-2 cause?
genital lesion, severe neurologic defects in neonates who get it congenitally
what does VSV cause?
chicken pox and shingles; transmitted via respiratory droplets
what do the immediate early genes products do?
they turn on the DNA replication genes - transcribed by proteins in the tegument
what do the early gene products do?
carry out DNA replication
what do the late gene products do?
they assemble viral particles
what DNA replication enzymes do HSV encode?
ribonucleotide reductase, thymidine kinase, helicase/primase, DNA polymerase
how does HSV-1 achieve latency and evade detection?
episomal DNA that inserts into trigeminal ganglia and expresses latency associated transcript (LAT)
how can HSV be reactivated?
trauma, stress, menstruation, UV light
what is a special biopsy finding in VZV?
multinucleated giant cells due to the enveloped glycoproteins binding to cell membranes
what does acyclovir do?
it is activated by viral thymidine kinase and then prevents DNA elongation by incorporating into DNA and preventing further DNA replication
it is an analog of guanosine
what does ganciclovir do?
it works for CMV which does not have a viral thymidine kinase - it is a viral protein kinase homologue activates it
what is forscarnet?
a pyrophosphate analog that binds directly to the pyrophosphate-binding sites of RNA or DNA polymerases
hard to use - needs to be given via IV and infusion pump
what is forscarnet?
it is a pyrophosphate analong that binds to the pyrophosphate binding pocket of RNA and DNA polymerases
downside: difficult to administer - needs to be IV with infusion pump
