SEARCH RESULTS FOR: Varicella-Zoster-Virus

Varicella Zoster Virus

Varicella Zoster Virus (VZV) - Chicken Pox: Pathogenesis and clinical findings Exposure to individual with VZV infection VZV enters respiratory tract & conjunctiva VZV enters dendritic cells (DC) DCs travel to regional lymph nodes Primary viremia Authors: Morgan Garland, Sean Spence VZV replicates VZV proteins ↑ major ↓ MHCI Reviewers: in nasopharynx histocompatibility expression Yan Yu, Danny Guo, & CD4+ T cells complex class I on CD4+ T Emily J. Doucette, (MHCI) degradation cell surface Laurie Parsons*, James D. Kellner* *MD at time of publication Acute phase VZV evades the immune system VZV travels through the blood in CD4+ T cells Immune cells release cytokines to fight the virus (stronger in adults) Fluid & cellular debris accumulate between epidermal layers Generalized pruritic (itchy) vesicular rash at different stages of development (macule, papule, vesicle) Immune system activates & releases inflammatory compounds VZV replicates in liver, spleen & lymph nodes Erythema (redness) & pain Scratching lesions introduces bacteria Fibroblasts lay down collagen to heal skin lesions Resets thermostat in hypothalamus Systemic response Tissue damage in oropharynx Direct inflammation in neural tissues Cerebellar ataxia (more common in children) Bacterial superinfection from S. aureus & Streptococcus pyogenes (more common in children) Scarring Fever (prodromal) Malaise (prodromal) Sore throat (prodromal) Encephalitis (more common in adults) Abscess Cellulitis Toxic shock syndrome (TSS) Secondary viremia Immune cells release cytokines to fight infection (stronger in adults) Inflammation & fluid build up in lungs VZV travels through the blood in CD4+ T cells expressing skin homing receptors Fluid & cellular debris accumulate in damaged alveoli Lungs more susceptible to secondary bacterial infection Pneumonia** (more common in adults) VZV colonizes keratinocytes over several days VZV colonizes neurons & glial cells in the brain VZV colonizes alveolar epithelial cells Resolution & latency VZV tracks along neurons from sites of infection to dorsal root ganglia & cranial nerves ↓ MHCI expression in sensory ganglia Adaptive immune system controls viremia ↓ Viral gene expression Resolution of VZV infection & development of lifelong immunity Direct viral toxicity (DNA damage, mitochondrial dysfunction, & protein misfolds in infected cells) Apoptosis & dysfunction of infected cells Latent infection Stress or immune suppression may precipitate reactivation of VZV later in life Shingles** **See corresponding Calgary Guide slide Pathophysiology Mechanism Published Nov 12, 2012; updated Jun 22, 2025 on www.thecalgaryguide.com Legend: Sign/Symptom/Lab Finding Complications