Medical Microbiology

424 8 VirusesasHumanPathogen

beparticularlyimportantareserologicallyproblematicalanyway.Serology

doescontributetoclearinguptheCMVstatusoftransplantrecipientsand

donors.

Epidemiology,prevention,andtherapy.CMVistransmittedbycontactor

smearinfection,usuallyinchildhoodoradolescence.Immunosuppressedpa-

tientscanbetreatedwithhyperimmunoglobulintoprovidepassiveimmu-

nityagainstinfectionorrecidivation.Ganciclovirandfoscarnetaretherapeu-

ticallyusefulintransplantation,andparticularlyinAIDSpatients,tocombat

CMV-inducedpneumonia,encephalitis,andretinitis.

Epstein-BarrVirus(EBV)

Pathogen,pathogenesis,clinicalpicture.EBVinfectsonlyanarrowspec-

trumofhostsandreplicatesveryslowly.ItpersistsinalatentstateinBlym-

phocytesandcanleadtotheirimmortalizationandtumortransformation.

EBVentersthebodythroughthemucosa.Itreplicatesinepithelialcellsof

theoropharynxorcervixandentersBlymphocytes,whereitcontinuesto

replicate.Thisresultsintheclinicalpictureofinfectiousmononucleosis(kis-

singdiseaseorPfeifferdisease),whichischaracterizedbyfeverandageneral-

izedbutmainlycervicalswellingofthelymphnodes,typicallyaccompanied

bytonsillitis,pharyngitis,andsomecasesofmildhepaticinvolvement.This

virusalsopersistsinlatency,probablyforthelifeofthepatient,in(immor-

talized)Bcells.

EBVandEBV-specificsequencesandantigensareisolatedincasesof

Burkittlymphomaandnasopharyngealcarcinoma.Thehigherincidenceof

BurkittlymphomainpartsofAfricaisattributedtoacofactorarisingfrom

thehyperendemicpresenceofmalariathere.EBVexacerbatestheB-cellpro-

liferationresultingfromamalariainfection.EBVhasalsobeenimplicatedin

HodgkindiseaseandT-celllymphomas.Thesetumorformsalsoresultfrom

theinteractionofEBVwithothermechanismsofcelldamage.Inimmuno-

competentpersons,thefollowinglymphoproliferativediseasesaresequelae

ofEBVinfections:

— abenignpolyclonalB-cellhyperplasia,

— itsmalignanttransformationintoapolyclonalB-celllymphoma,and

— amalignant,oligoclonalormonoclonalB-celllymphoma.

Diagnosis.Heterogeneticantibodiesthatagglutinatetheerythrocytesof

severalanimalspeciesandantibodiestoavarietyofviralantigensarefound

inacuteinfectiousmononucleosis:

— VCA(viralcapsidantigen).AntibodiestoVCAappearearlyandpersistfor

life.

— EA(earlyantigen).AntibodiestoEAareonlydetectableduringtheactive

disease.

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Kayser, Medical Microbiology © 2005 Thieme