POX AND HERPESVIRUSESJaime A. Santos

Saturday, May 29, 2010

Poxviruseslargest viruses

complex symmetrydouble-stranded DNAassembled in inclusion

bodies (Guarnieri bodies)

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Diseasesvariola (smallpox)

vaccinia

orf

cowpox

monkeypox

othe animal poxviruses

molluscum contagiosum

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Smallpoxonly infectious disease to have been eliminated by vaccination

2 forms: variola major (high mortality), variola minor

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Smallpox vaccination

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Molluscum contagiosum

diagnosis: molluscum bodies

treatment: cryotherapy or electrodesication

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Herpesviridae

HSV-1

HSV-2

VZV

EBV

CMV

HHV-6, 7, 8

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Characteristics

large, enveloped, icosahedral

encode DNA polymerase

latency, persistence

very common causes of infection

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HSV 1 and 2

HSV-1 more common in oral lesions; HSV-2 in genital lesions

majority asymptomatic; skin and mucous membrane lesions, encephalitis, keratitis

congenital infection

diagnosis: serology, culture

treatment: acyclovir and related drugs

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Herpes simplex 1

and 22 different viruses related

to each otherlatency in nerve ganglia

reactivation

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Varicella-zoster virus

chickenpoxHerpes zoster (reactivation)

congenital varicella

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Varicella (chickenpox)

self-limiting; incubation 2 weeks

milder in children

severe in neonates whoe mothers had chickenpox <5 days prior to delivery, in adults and in immunocompromised

diagnosis often clinical but can be cultured

treatment: acyclovir

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Epstein-Barr virus

infects B lymphocytes - receptor is complement receptor on B cell

B cell infection leads to immortalization and polyclonal B cell stimulation

transmitted thru saliva

causes infectious mononucleosis

possibility of inducing transformation

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Infectious mononucleosis

fever, lymphadenopathy, hepatosplenomegalyatypical lymphocytes (Downey cells)

heterophil antibodies

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Infectious Mononucleosis

Epidemiology: different in

developing countries

Diagnosis: atypical lymphocytes

+ Monotest for heterophilantibodies

serology: + IgM anti-VCAculture: difficult

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Atypical lymphocytes

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EBV infection

has been associated with endemic type of Burkitt’s lymphoma and nasopharyngeal carcinoma

no practical treatment with antiviral

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Cytomegalovirusvery common infection

most common cause of congenital viral infection and most common infectious cause of deafness

present in body fluids

asymptomatic; pneumonia; disseminated in immunocompromised e.g. AIDS

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CMV Involvement

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Congenital CMVasymptomatic to full-blown

risk in second pregnancy lower

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CMV Diagnosis

cytology

serology

culture

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CMV Treatment

with ganciclovir

limited to life-threatening infection and retinitis

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HHV 6

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Roseola infantum

common exanthem of infants

relatively benignfever for about three

days followed by rashes

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HHV-8has been associated with

Kaposi’s sarcoma

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THANK YOU!

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