Varicella-Zoster Virus

Questions

1. What are the two main diseases caused by HHV-3?

2. Describe how VZV can cause chickenpox, and its complications?

3. Describe how VZV can be diagnosed?

4. Describe the treatment involved for VZV?

5. What are the preventative measures that can be taken to prevent VZV?

6. Describe how shingles can be caused, and its complications, its diagnosis, and treatment?

Varicella-Zoster Virus (HHV3) causes chickenpox and shingles. Chickenpox is transmitted to others via inhalation of respiratory droplets from infection patients, or via live direct contact with skin lesions. Can cause secondary skin sepsis and other complications for immunocompromised patients. Diagnosis is via clinical means, appearance of distinctive rash and also EM – looking for herpes virus in vesicles – if undetermined then use fluorescent serology. Treatment is given as supportive therapy, use antiviral agents – acyclovir, famciclovir, valaciclovir for patients with respiratory symptoms and immunocompromised. Aspirin is contraindicated because it can cause Reye’s syndrome. This virus can be prevented by administering a live attenuated vaccine – recently approved called “Varivax” – 12-18 month old babies are given this with MMR (may need 2^nd dose). Immunocompromised patients are given (ZIG) – Zoster Immune Globulin for passive protection. Zoster causes shingles – this can occur when reactivation of VZV in DRG or extramedullary cranial nerve ganglion occurs. Treatment is same as VZV + effective analgesia, and diagnosis is only by clinical means ≫ distinctive rash.

Category: Microbiology Notes