Herpes zoster Causes

Herpes zoster Causes - Upon reactivation, the virus...

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Herpes zoster Causes The causative agent for Herpes Zoster is the Varicella Zoster Virus (VZV), a double-stranded DNA virus related to the Herpes simplex virus group. Most people are infected with this virus as children, and suffer from an episode of chickenpox. The immune system eventually eliminates the virus from most locations, but it remains dormant in the ganglia adjacent to the spinal cord or the ganglion semilunare in the base of the skull. Herpes Zoster results from the virus reactivating in a single sensory ganglion. In contrast to Herpes simplex virus, the latency of VZV is poorly understood. The immune system suppresses reactivation of the virus and prevents herpes zoster unless it is compromised. Why this suppression sometimes fails is poorly understood, but herpes zoster is more likely to occur in people whose immune system is impaired due to aging, immunosuppressive therapy, psychological stress, or other factors.
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Unformatted text preview: Upon reactivation, the virus replicates in the nerve cells, and virions are shed from the cells and carried down the axons to the area of skin served by that ganglion. In the skin, the virus causes local inflammation and blisters. As with chickenpox and/or other forms of herpes, direct contact with an active rash can spread VZV to a person who has no immunity to the virus. This newly infected individual may then develop chickenpox, but will not immediately develop shingles. Epidemiology The incidence rate of herpes zoster ranges from 1.2 to 3.4 per 1,000 person-years among healthy individuals, increasing to 3.911.8 per 1,000 person years among those older than 65 years. Herpes zoster affects both genders equally and may develop in any age group, but its incidence is increased in those Older than 60 Who had chickenpox before age 1 Whose immune system is weakened by medications or disease...
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This note was uploaded on 12/04/2011 for the course ANTHRO 2000 taught by Professor Monicaoyola during the Fall '10 term at Broward College.

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