Категории: Все - treatment - epidemiology - diagnosis - prevention

по R G 15 лет назад

627

B3: Herpes

Various forms of herpes viruses, such as HH6, HH7, and HH8, along with Epstein-Barr virus (EBV), are discussed, highlighting their clinical manifestations and associated diseases. HH6 infects almost all children by age two and can cause symptoms similar to mononucleosis.

B3:  Herpes

Herpes

General

Sensitivity

Organic solvent

Thermolabile

Replication

Where does replication occur?

Nucleus

Structure

Lipid envelope

Icosahedral

Linear dsDNA

Others

HH8
Kaposi's Sarcoma
HH7
May cause mononucleosis-like syndrome
Almost all children infected by age 2
Resembles HH6
HH6

VZV

VZV Ig
Live, attenuated vaccine
Immunological test

For Ag detection

Chickenpox
Shingles

CMV

Transplacental transmission

Most common transplacentally transmitted infection in the U.S.

Resembles infectious mononucleosis

No heterophile Ab

Owl's eyes

Enlargement of infected cells with pronuclear inclusions

EBV

Supportive
No specific AV
Early infection

leads to..

Benign disease

Subtopic
Monospot

Heterophile antibodies

Cross-react w/ sheep, goat RBCs

Heterophile Ab

All of these may serve as buzzwords

Immunosuppressed

Oral Hairy leukoplakia

B cell lymphoma

African Burkitt's lymphoma

Where would you find a high incidence of African Burkitt's lymphoma?

Regions w/ high incidence of malaria

Non-Hodgkin's lymphoma
Nasopharyngeal carcinoma

Where is it endemic?

China

Hodgkin's Disease
Infectious mononucleosis
Downey cells

Atypical lymphocytes

HSV

Treatment
Requires activation by viral thymidine kinase
Foscarnet

When resistant to acyclovir

Valacyclovir

Valacyclovir or "Valtrex" is a prodrug of...

Acyclovir

  • Decreases severity of primary infection
  • I.V. for encephalitis and neonatal infections
  • Prevention
    Experimental vaccines

  • Herpevac
  • dl5-29
  • C-section
    Avoid contact esp. sexual
    Epidemiology
    Predisposing factors

    SES

    Immuno. status

    Place

  • Where in the world will you find Herpes?
  • What is the reservoir?
  • Humans only reservoir

    Transmission

    Asymptomatic shedding

    Direct contact w/ infected secretions

    Diagnosis
    Serology

    Only for primary infection

    EIA

    Antigen detection

    Tzanck smear

    Scrape the lesion

    Isolation in cell culture

    Most definitive

    Clinical
    HSV-2

    Clinical manifestations of HSV-2 infection

    1. Primary infection presents as papules progressing to vesicles and pustules,

    lymphadenopathy and tenderness, 3-4 weeks duration

    2. Recurrent infection characterized by prodrome followed by groups of vesicles on external genitalia, 1-2 weeks duration

    3. Neonatal herpes usually due to HSV-2 acquired by passage through infected birth

    canal; 60% mortality with survivors suffering neurologic sequelae; disseminated vesicular lesions with internal organ involvement

    Neonatal herpes

    HSV-1

    Clinical manifestations of HSV-1 infection

    1. Primary infection often asymptomatic; 50-90% of population is seropositive

    2. Primary gingivostomatitis—fever, irritability, painful vesicular lesions on buccal

    mucosa, tongue, gums, throat, 1-2 weeks duration

    3. Recurrent infection characterized by prodrome, followed by unilateral vesicles of 1

    week duration

    4. Ocular lesions can lead to permanent corneal scarring

    5. Causes 10% of viral encephalitis with 70% mortality if untreated

    Genital herpes

    Encephalitis

    Ocular herpes

    Herpetic whitlow

    Fever blisters

    Gingivostomatitis

    Characteristics
    Pathophysiology

    Pathophysiology of infection

    1. Acute infection results in multinucleated cells (syncytia), ballooning degeneration of epithelial cells, necrosis, inclusion bodies, inflammatory response, cell to cell spread, latent infection of ganglia

    2. Latent infection does not destroy ganglia; viral genome persists as circular DNA; reactivation of virus replication leads to recurrent disease

    3. Recurrence triggered by stress, ultraviolet light, hormonal flux

    4. Spreads from cell to cell in presence of antibody

    5. Cell-mediated immunity contributes to symptoms and resolution

    Triggers for recurrence

    Hormonal flux

    UV light

    Stress

    Syncytia