Herpes Virus + Herpes Simplex Virus (Murray 3rd Ed pp 421)

Questions

1. What are the basic properties of a Herpes virus?

2. What are the basic characteristics exhibited by the Herpes virus?

3. How many Herpes viruses are there, name them all?

4. Describe the primary infections caused by HSV 1-2, including site of replication, recurrence factors, and recurrent infections?

5. How would you diagnose HSV 1&2?

6. How could you prevent this virus?

7. How could you provide treatment for this virus?

Herpes viruses are DNA, icosahedral, enveloped viruses that are between 150-200nm in size. They exhibit latency (i.e.: always present once infected), primarily affect nervous and lymphoid tissue (sometimes both), and have oncogenic potential. There are 8 herpes viruses and these are: HSV1-2, Varicella-Zoster V, Epstein Barr V, Cytomegalovirus, HHV6-8. HSV1-2 usually multiply in skin and mucous membranes, can infect sensory ganglia (i.e.: CNV, and sacral) travelling via sensory nerves, lying dormant for some time before being reactivated causing recurrent infections. Primary infections are usually asymptomatic (90%) but manifestations include (GASWEKNE – “GAS with electricity kauses numerous effects” ):

• gingivostomatitis (HSV1),
  
• ano-genitial herpes (HSV2),
  
• skin herpes,
  
• whitlow,
  
• eczema herpeticum,
  
• keratoconjunctivitis,
  
• neonatal herpes, and
  
• herpes encephalitis.
  
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• Recurrence can be influenced by stress, cold, sunlight, immunosuppression, fever, menstrual cycle, trauma/manipulation. Recurrent infections include: cold sore, skin herpes, genital herpes, and whitlow. Diagnosis can be done by taking a swab and preparing a Tzanck smear, looking for “CPE”. Isolating the virus and looking for balloon degeneration, syncytia, and intracellular inclusions. You can also use fluorescent antisera to form bodies, therefore identify the virus. Prevention: wear gloves when handling infected material, barrier contraceptives, safe-sex practices + sexual abstinence, C-sections for pregnant infected mothers. Treatment is by antivirals including, aciclovir, famciclovir (genital herpes), penciclovir (topical and ophthalmic agents)

Category: Microbiology Notes