HSV 1 and 2

Question 1

HSV 1 and 2 replicate where?

Answer 1

Epithelial cells

Question 2

Where do HSV 1 and 2 reside?

Answer 2

trigeminal or sacral ganglia

Question 3

HSV structure?

Answer 3

Large, ds DNA, icosahedral capsid, lipid envelope

Question 4

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

Answer 4

Know

Question 5

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

Answer 5

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

Question 6

What are early proteins?

Answer 6

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

Question 7

Examples of early proteins?

Answer 7

Thymidine Kinase and DNA polymerase

Question 8

What is clinicaly important about thymidine kinase?

Answer 8

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

Question 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.

Answer 9

ok

Question 10

Thymidine kinase mutants seen most often in?

Answer 10

AIDS pts

Question 11

Viral DNA polymerase is the ultimate target of….

Answer 11

Acyclovir

Question 12

The “late” proteins encode what?

Answer 12

capsomeres, envelope glycoproteins, other structural proteins

Question 13

Virus assembly occurs where ?

Answer 13

Nucleus

Question 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).

Answer 14

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

Question 15

Which diagnostic test for HSV tests for Syncytia?

Answer 15

Tzanck Smear

Question 16

What specifically does a Tzanck Smear look for?

Answer 16

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

Question 17

During latency, HSV’s virus genome is stored

Answer 17

extrachromosomally

Question 18

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

Answer 18

LAT (Latency associated transcript)

Question 19

What is LAT

Answer 19

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

Question 20

HSV 1 is traditionally

Answer 20

Above the belt

Question 21

HSV 2 is traditionally

Answer 21

Below the belt

Question 22

Disseminated disease caused by HSV is a problem among who?

Answer 22

Immunocompromised patients and neonates

Question 23

Symptoms

Answer 23

• 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.

Question 24

Recurrent infections occur when

Answer 24

When cell mediated immunity is low

Question 25

Primary gingivostomatitis

Answer 25

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

Question 26

Recurrent oral infections generally result in

Answer 26

fever blisters

Question 27

HSV 2 genital infections recur more frequently that HSV1 genital infections

Answer 27

ok

Question 28

KNOW

Answer 28

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

Question 29

Ocular HSV

Answer 29

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

Question 30

Keratitis

Answer 30

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

Question 31

Encephalitis is a result of:

Answer 31

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

Question 32

Herpes encephalitis is severe

Answer 32

70% mortality if left untreated

Question 33

Meningitis

Answer 33

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

Question 34

Genital herpes diagnosis

Answer 34

• 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: