herpesviruses Flashcards
what are the human herpesviruses? (list)
1: HSV-1 (HHV-1)
2: HSV-2 (HHV-2)
3: varicella-zoster (HHV-3)
4: epstein-barr virus (HHV-4)
5: cytomegalovirus (HHV-5)
6: human herpesvirus 6 (HHV-6)
7: huma herpesvirus 7 (HHV-7)
8: kaposi’s sarcoma herpesvirus (HHV-8)
what is the one non-human primate herpesvirus of medical importance?
cercopithecine herpesvirus 1 (b-virus)
what is the virion structure of herpes viruses?
icosahedral core surrounded by lipoprotein envelope
what is the herpes virus genome structure?
linear
double-stranded DNA
does the herpes virion contain a polymerase?
no
where in the cell do herpes viruses replicate?
in the nucleus
where do herpes viruses get their envelope?
they’re the only viruses to obtain their envelope by budding from the nuclear membrane, lose it, then get a new membrane from the host’s plasma membrane (Leib said detail wasn’t required)
what is the tegument in herpes viruses and where is it found?
between nucleocapsid and the envelope
contains regulatory proteins s.a. transcription and translation factors, that play a role in viral replication
what are latent infections?
acute disease followed by asymptomatic period during which virus is quiescent
patient exposed to inciting agent or immunosuppressed, reactivation of replication and disease can occur
symptoms can be similar or different
how does HSV maintain its quiescent state?
after HSV infects neurons, set of latency-associated transcripts synthesized
these suppress viral replication
what are latency-associated transcripts and what viruses use them? what do they allow these viruses to do?
noncoding regulatory RNAs that suppress viral replication
used by HSV to allow for latent infection
how does CMV maintain its quiescent state?
produces microRNAs that inhibit translation of mRNA required for viral replication
genome also encodes protein and RNA that inhibits apoptosis in infected cells - allows infected cell to survive
which viruses cause vesicular rash? which infections (primary or secondary) would you expect to see it?
herpes simplex virus types 1 and 2; varicella-zoster virus
occurs both in primary infections and reactivations, though primary infections usually more severe
which herpesviruses can induce the formation of multinucleated giant cells?
herpes simplex virus 1 and 2
varicella-zoster virus
cytomegalovirus
what are the three classes of herpesvirus? how is it determined which class the viruses go into
classified by the type of cells they infect:
alpha herpesviruses: herpes simplex viruses 1 and 2
varicella-zoster
- infect epithelial cells primarily, cause latent infection in neurons
beta herpesviruses:
cytomegaloviruses
human herpesvirus 6
- infect and become latent in variety of tissues
gamma herpesviruses:
epstein barr
human herpesvirus 8 (kaposi’s…)
- infect and become latent primarily in lymphoid cells
give the following details about HSV-1:
- giant cells produced? - fetal or neonatal disease important? - lab diagnostic technique? - antiviral therapy commonly used?
- yes
- no
- culture
- acyclovir
give the following details about HSV-2:
- giant cells produced? - fetal or neonatal disease important? - lab diagnostic technique? - antiviral therapy commonly used?
- yes
- yes
- culture
- acyclovir
give the following details about VZN:
- giant cells produced? - fetal or neonatal disease important? - lab diagnostic technique? - antiviral therapy commonly used?
- yes
- no
- culture
- acyclovir
give the following details about CMV:
- giant cells produced? - fetal or neonatal disease important? - lab diagnostic technique? - antiviral therapy commonly used?
- yes
- yes
- culture
- ganciclovir
give the following details about EBV:
- giant cells produced? - fetal or neonatal disease important? - lab diagnostic technique? - antiviral therapy commonly used?
- no
- no
- heterophil Ab (which is -ve in CMV-induced mono-like symptoms; Leib skipped this in lec)
- none
give the following details about HHV-8:
- giant cells produced? - fetal or neonatal disease important? - lab diagnostic technique? - antiviral therapy commonly used?
- no
- no
- DNA probes
- alpha interferon
what structural factors distinguish HSV-1 from HSV-2?
structural factors: structurally and morphologically indistinguishable but can be differntiated by restriction endonuclease patterns of genome DNA and by type-specific monoclonal antisera
what will HSV-1 cause?
- Oral
- acute gingivostomatitis- recurrent herpes labialis (cold sores)
- Ocular
- keratoconjunctivitis (herpetic stromal keratitis) -> blindness
- Dendritic ulcer
- Retina destruction
- encephalitis (primarily in adults)
- Also genital vesicles (due to, uh, unusual sexual positions)
what will HSV-2 cause?
herpes genitalis
neonatal encephalitis
aseptic meningitis