Microbiology-Viral Skin Infections Flashcards
What are the alpha herpesviruses?
HSV-1, HSV-2, VZV
What diseases result from HSV-1 infection?
ABOVE THE WAIST: Cold sores, fever blisters, keratitis, CNS infection and encephalitis
What diseases result from HSV-2 infection?
BELOW THE WAIST: Genital lesions and CNS
What diseases result from herpes zoster (VZV) infection?
Chicken pox and shingles
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.
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.
How does herpesvirus infect a cell?
It is an enveloped virus so it just fuses with the plasma membrane.
What factors can activate herpesvirus?
Stress, UV, Trauma and Menstruation
Where does the herpesvirus exit the neuron?
Axonal terminal
When are people at most risk for reactivation of herpesvirus?
Old age when cell-mediated immunity wanes
Where does HSV-1 remain during latency?
Trigeminal nerve
Where does VZV remain during latency?
Dorsal root ganglia
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.
Where is maternal immunity deficient in protecting their neonate from HSV-2?
When the mother has a primary reaction.
What virus causes this?
HSV, can lead to blindness
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.
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.
