Herpes Viruses Flashcards
Are herpesviruses DNA or RNA viruses?
dsDNA linear
Are herpesviruses enveloped?
Yes
What is the most common cause of sporadic encephalitis?
HSV-1
How is HSV-1 transmitted?
Respiratory secretions
Saliva
What diseases does HSV-1 cause?
Sporadic encephalitis
Oral/genital lesions
Keratoconjunctivitis
What diseases does HSV-2 cause?
Genital/oral lesions
Neonatal herpes
Where does HSV-2 reside in the latent stage?
Sacral ganglia
What drugs are guanosine analogs used to treat HSV and VZV.
Acyclovir
Famciclovir- herpes zoster
Valacyclovir- pro drug of acyclovir that has better oral availability
What is the mechanism of action of acyclovir?
Guanine analog.
Monophosphorylated by HSV/VZV thymidine kinase.
Triphosphate formed by cellular enzymes.
Inhibits viral DNA polymerase.
Why does acyclovir have few side effects?
It must be phosphorylated by viral thyidine kinase.
What diseases are caused by VZV?
Chicken pox
Shingles (zoster)
Encephalitis
Pneumonia
Where does VZV reside in the latent stage?
Trigeminal ganglia
Dorsal root
How is VZV transmitted?
Respiratory secretions
What is the most common complication of shingles?
Post herpatic neuralgia
Characterize the clinical findings of mononucleosis.
Fever
Hepatosplenomegaly
Pharyngitis
Lymphadenopathy- especially posterior cervical
How is EBV transmitted?
Respiratory secretions
Saliva
How is HSV-2 transmitted?
Sexual contact
Perinatally
What is the characteristic histologic appearance of CMV infection?
Owl eye inclusions
Where does CMV reside during latency?
Mononuclear cells
How is HHV-6/HHV-7 transmitted?
Saliva
What disease is caused by HHV-6/HHV-7?
Roseola- high fevers that can cause seizures (days) followed by diffuse macular rash
How is HHV-8 transmitted?
Sexual contact
What disease is caused by HHV-8?
Karposi sarcoma
What is Karposi sarcoma?
Neoplasm of endothelial cells
Describe the dermatologic findings of Karposi sarcoma.
Dark/violaceous plaques or nodules- represents vascular proliferation
How do you identify HSV in a patient with skin/genital vesicles?
Tzanck test- smear of opened skin vesicle to detect multinucleated giant cells
How do you identify a herpesvirus in a patient with encephalitis?
CSF PCR
Where does encapsidation of herpesviruses occur?
Nucleus- intranuclear inclusions
What herpesvirus do heterophile antibodies indicate?
EBV infection
What malignancies are associated with EBV?
Burkitt lymphoma B-cell lymphoma Leiomyosarcoma Hodgkin lymphoma Nasopharyngeal carcinoma Gastric adenocarcinoma
