HSV 1 and 2 Flashcards Preview

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Flashcards in HSV 1 and 2 Deck (34):
1

HSV 1 and 2 replicate where?

Epithelial cells

2

Where do HSV 1 and 2 reside?

trigeminal or sacral ganglia

3

HSV structure?

Large, ds DNA, icosahedral capsid, lipid envelope

4

After viral attachment, HSV fuses with the plasma membrane in a pH- INDEPENDENT MANNER

Know

5

What is significant about the initial transcription/translation (immediate early expression) process for HSV?

produces proteins that act as transcriptional regulators that modify host RNA polymerase so that it preferentially transcribes viral genes over host genes.

6

What are early proteins?

Proteins whose role is to replicate virus genome to produce progeny genomes.

7

Examples of early proteins?

Thymidine Kinase and DNA polymerase

8

What is clinicaly important about thymidine kinase?

it is needed to phosphorylate acyclovir and its derivatives. Acyclovir is the DOC in most HSV infections

9

ACV is interesting because, due to it needing the viral thymidine kinase in order to be activated, it is much more specific for infected cells than non-infected cells. However, Thymidine kinase mutants are often resistant to ACV.

ok

10

Thymidine kinase mutants seen most often in?

AIDS pts

11

Viral DNA polymerase is the ultimate target of....

Acyclovir

12

The "late" proteins encode what?

capsomeres, envelope glycoproteins, other structural proteins

13

Virus assembly occurs where ?

Nucleus

14

KNOW THIS: Because the viral glycoproteins responsible for the initial fusion/ entry are still present in the plasma membrane of the infected cells late in infection, infected cells can fuse with adjacent uninfected cells. This leads to the formation of syncytia (cells with more than one nucleus).

This means that HSV can spread from cell to cell without the formal release of virus progeny.

15

Which diagnostic test for HSV tests for Syncytia?

Tzanck Smear

16

What specifically does a Tzanck Smear look for?

Smears of cells are taken from an ulcerous lesion and viewed under a microscope looking for multinucleated giant cells with Nuclear Inclusion Bodies

17

During latency, HSV's virus genome is stored

extrachromosomally

18

The only HSV gene expressed during the maintenance of latency is called

LAT (Latency associated transcript)

19

What is LAT

it is a gene that codes an RNA species that silences a subset of cellular genes to prevent apoptosis

20

HSV 1 is traditionally

Above the belt

21

HSV 2 is traditionally

Below the belt

22

Disseminated disease caused by HSV is a problem among who?

Immunocompromised patients and neonates

23

Symptoms

- significant percentage = asymptomatic
- if symptomatic, multiple blisters form on the infected skin about two weeks following infection. These blisters rupture and produce mildly to severely painful lesions which take up to 2 weeks to heal.

24

Recurrent infections occur when

When cell mediated immunity is low

25

Primary gingivostomatitis

Vesicles occur on the lips, tongue, and facial skin surrounding the mouth

26

Recurrent oral infections generally result in

fever blisters

27

HSV 2 genital infections recur more frequently that HSV1 genital infections

ok

28

KNOW

virus shedding can occur in the absence of recurrent vesicles and well after lesions are unapparent

29

Ocular HSV

Blepharitis and conjunctivitis are most often seen in children and are usually present as small vesicles or pustules around the eye lid

30

Keratitis

can result in significant corneal scarring if left untreated, chartacteized by red painful eye, blurred vision, photophobia

31

Encephalitis is a result of:

result of recurrent HSV1 in adults and primary HSV 2 in neonates

32

Herpes encephalitis is severe

70% mortality if left untreated

33

Meningitis

occurs in 10% of primary HSV 2 and is goes away in a week usually

34

Genital herpes diagnosis

- Culture: takes 3-10 days depending on the inoculum for the cytopathic effect to appear
- Flourescent antibody screeening
- Serology: detects antibody to glycoprotein G , can distinguis 1 and 2 but only indicates past infection
- Tzanck smear: