Chapter 41- Herpesviridae HSV & VZV Flashcards
characteristics of herpes
large enveloped icosahedral nucleocapsid. Has double stranded DNA. Able to establish lifelong latent infections. Brings the gene for its own polymerase.
The three alphaherpesvirus’s and their diseases
1) HSV-1: fever blisters
2) HSV-2: genital lesions
3) Varicella zoster (vzv): chicken pox and shingles
The three betaherpesvirus’s and diseases
1) cytomegalovirus (CMV): usually asymptomatic but in AIDS patients causes retinitis and pneumonia.
2) Human herpes 6 (HHV-6): Roseola and systemic disease in AIDS
3) HHV-7: Roseola
The two gammaherpesvirus’s and diseases
1) Epstein Barr: mono, and Hodgkin disease
2) Kaposi Sarcoma herpes: Kaposi sarcoma
HSV1 &2
painful but benign lesions with recurrence. epithelial cells are destroyed by the replication of the virus vesicular lesions. host defenses (cell mediated immunity) resolve the local lesion but host defenses do NOT resolve latency.
what happens to the virus during primary infection
The virus enters peripheral sensory nerves and migrates along axons to sensory nerve ganglia in the CNS. This allows the virus to escape the immune response.
Why is diagnosis of herpes early better?
viral shedding diminishes and negative test results could be false negatives.
primary infection and pregnancy
it can transmit to the baby during late pregnancy.
Shingles description
varicella virus migrates to ganglion. lesions occur in restricted areas enervated by single ganglion.
complications of herpes zoster
1) ocular- reduced vision
2) neurologic- myelitis, encephalitis, cranial nerve palsies.
3) VZV- pneumonia, hepatitis.
Varicella vaccine
Live attenuated vaccine given in 2 doses.
Zoster vaccine
same strain as varicella vaccine, but more virus
