1Disease Classification
Varicella (chicken pox) and Herpes zoster (shingles)
2Causative Agent
Varicella-zoster virus (VCV) or Human herpevirus 3 (HHV-3)
3GTKYCA
Enveloped, 150-200 nm, genome double stranded DNA, produces latent infection, targets sensory neuron
4Epidemiology: Reservoir
Humans
5Epidemiology: POE
Respiratory System
6Epidemiology: MOT
Aerosol, mother to fetus
7Incubation Period
10-21 days
8Pathogenesis
Replicates in respiratory tract and spreads to lymph nodes, blood stream, and skin. Viral replication in skin results in vesicular lesions and spread to sensory neurons. Viral genome enters the nucleus in dorsal root ganglion where it remains dormant. Replication of latent virus and resumes in adulthood and produces a skin rash in regions of nerve fiber innervation
9Symptoms
Fever, fatigue, Vesivular rash (3-4 days), shingles
10Vesicular Rash
Primarly face, throat, and lower back. less frequent chest and shoulders. Vesicles fill with pus, rupture and form scabs
11Shingles Symptoms- Lantent Infection that occurs after age 50
localized to skin innervated by infected sensory neurons- generally unilateral thorax; hypersenstivity, pain, vesicular rash
12Complications
Secondary infections, Pneumonia, Reye’s Syndrome (<37cases/yr), Encephalitis, mortality rate for varicella 1-1.5/40k cases; Shingles (incidence of 1 in 3)
13Reye’s Syndrom
Swelling of brain and liver, diarrhea, rapid breathing, vomiting, and severe fatigue. Brain dysfunction; drowiness, confusion, seizures, loss of consciousness. Permant brain damage. Mortality- 30%. Additional rish factor- children and adolescents that take aspirin
14Shingles Complications
Necrosis, persitent hypersensitivity (lasts months), Postherpetic neuralgia (buring or stinging- chronic pain), Ramsay Hunt
15Prevention- Vaccination
Varicella- MMRV, First dose 12-15 months, Booster 4-6 yrs; Zoster (50-90% effective) Shingrix (2017), after age 50, 2 doses 2-6 months apart
16Treatment
Acyclovir, Antihistamine, Analgesics