http://www.herpes.on.net/cold_sores/Default.htm

I. Background

25 viruses in the family Herpetoviridae-

a number of these are known to infect man:

– herpes simplex virus (HSV)

– Epstein-Barr virus (EBV)

– cytomegalovirus (CMV)

– varicella-zoster virus (VZV)

– human herpes 6 & 7 (exanthum subitum & roseola infantum)

– HHV 8 (Kaposi’s sarcoma-associated).

II. Classification

Viruses of Humans Common Name Subfamily

Human herpesvirus 1 Herpes simplex type1 alpha

Human herpesvirus 2 Herpes simplex type 2 alpha

Human herpesvirus 3 Varicella -zoster alpha

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Virus Subfamily primary terget cell Site of Latency Spread

Herpes Simplex Virus I a mucoepithelial Neuron close contact

Herpes Simplex Virus II a mucoepithelial Neuron close contact

Varicella Zoster Virus a mucoepithelial Neuron close contact,

respiratory droplets

Human Herpesviruses

HSV(1,2)

Life-long Latency

IV. Neurovirulence and Latency in

HSV

– Virus lies dormant for a period of time but may become reactivated even in the presence of neutralizing antibodies.

– Sensory ganglia are the source of virus that produces recurrent skin lesions-

– trigeminal ganglia in type 1

– sacral ganglia in type 2

Three manifestations of HSV

latencyKey Feature: there is a wide spectrum of clinical

presentations

•Some individuals (5 - 10%) have frequent clinical

reactivation

•Most individuals reactivation is clinically asymptomatic

•In ALL cases, virus is shed

HSV Disease

Clinical findings:

HSV-1

1) acute Gingivostomatits

2) herpes Labialis( fever blisters or cold sores)

3) Keratoconjunctivitis

4) Encephalitis

5)Herpetic withlow

Eczema herpeticum

6)Disseminated infections in immunocompromised patients( s.a. esophagitis, pneuminia)

HSV Disease:

Recurrent Infection

Cold sores (labialis)

Genital lesions (herpes genitalis)

Keratoconjunctivitis

Encephalitis

Meningoencephalitis

Eczema/Herpes

Herpes Simplex Virus type 2

•Infects the genital tract

•Is sexually transmitted

•Complicates childbirth

HSV-2

1) Genital herpes

2) Neonatal herpes

3) Aseptic meningitis

Diagnosis of Herpes Simplex Virus

Infections:

•Viral Culture

•Tzanck prep

•Culture with monoclonal antibody staining

•Serology

•Polymerase chain reaction (PCR)

Two Unique Features of VZV:

•Airborne spread or skin to skin contact

•More severe infection if primary infection

occurs as an adult

Complications of Varicella

•Reye’s Syndrome

•Bacterial Superinfection of lesions (more common in younger

patients)

•Varicella pneumonia

•Neonatal varicella -- disseminated, 30% mortality

Varicella patients at risk

•ADULTS

•PREGNANCY (3rd trimester)

•IMMUNOCOMPROMISED

•The mortality rate for varicella pneumonia in leukemic

children receiving chemotherapy is 1,000 times higher than

in healthy children.

Note: Children with isolated agammaglobulinemia are not at risk!

Neonatal Varicella

Zoster

Complications of Zoster

Postherpetic Neuraligia

•Affects 25 - 50% of zoster patients over 50

•Pain may persist for months or even years

Varicella Vaccine

•Prevents 40 - 70% of chickenpox occurrence

•Greatly reduces the severity in the rest

•Attenuated virus

•Can still establish latency and reactivate

Question: How long will immunity last?

V. Treatment and Control

Chemotherapy:

HSV and VZV…. acycloguanosine (acyclovir) and prodrugs valacyclovir and famciclovir (famciclovir is prodrug of penciclovir)

CMV…ganciclovir; phosphonoacetate, interferon