Microbiology-Viral Skin Infections Flashcards Preview

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Flashcards in Microbiology-Viral Skin Infections Deck (21)
1

What are the alpha herpesviruses?

HSV-1, HSV-2, VZV

2

What diseases result from HSV-1 infection?

ABOVE THE WAIST: Cold sores, fever blisters, keratitis, CNS infection and encephalitis

3

What diseases result from HSV-2 infection?

BELOW THE WAIST: Genital lesions and CNS

4

What diseases result from herpes zoster (VZV) infection?

Chicken pox and shingles

5

Why do viruses go latent when they infect neurons? How does herpesvirus reactivate itself?

Neurons are quiescent and no longer replicate. Herpesvirus can code for limited dNTPs to replicate itself, leave and infect neighboring epithelial cells.

6

What are good target genes for antiviral drugs targeting herpes zoster in neurons?

Genes encoding for DNA synthesis machinery in the viral genome so it cannot reactivate itself.

7

How does herpesvirus infect a cell?

It is an enveloped virus so it just fuses with the plasma membrane.

8

What factors can activate herpesvirus?

Stress, UV, Trauma and Menstruation

9

Where does the herpesvirus exit the neuron?

Axonal terminal

10

When are people at most risk for reactivation of herpesvirus?

Old age when cell-mediated immunity wanes

11

Where does HSV-1 remain during latency?

Trigeminal nerve

12

Where does VZV remain during latency?

Dorsal root ganglia

13

Why is recurrence of viral infection less serious than a primary infection?

Cell-mediated immunity is already prepared to fight the virus and the virus had limited resources to replicate itself.

14

Where is maternal immunity deficient in protecting their neonate from HSV-2?

When the mother has a primary reaction.

15

What virus causes this?

HSV, can lead to blindness

16

What is a highly accurate way of diagnosis of VZV?

Tzanck smear. It's a biopsy of the vesicular lesion where you are looking for syncytial cells.

17

What are the main drugs for targeting herpes?

Acyclovir (targets herpes thymidine kinase) and PAA (targets herpes DNA polymerase)

18

How does acyclovir inhibit thymidine kinase?

It does not have a 3' end or any sugar for that matter to continue DNA elongation. Once it is made into a triphosphate it is incorporated into viral DNA and replication stops.

19

What is the antiviral of choice for CMV?

Ganciclovir

20

What is antiviral is used that binds to DNA polymerase pyrophosphate-biding sites?

Forscarnet

21

Why is Varivax the recommended vaccine for everyone except those who are immune compromised?

It is a live attenuated virus that generates immunity at the site that needs it the most.