Medical Microbiology

426 8 VirusesasHumanPathogen

followingorgantransplantationsandisasignificantcauseofdeathinAIDS

patients(1 2 %).

ThecontributionofHHV 8 tothepathogenesisofKaposisarcomaappears

tolieindysregulationofcytokineandhormoneproduction.Intransplan-

tation-associationKaposisarcomatheviruscanalsobetransmittedbythe

transplant.

Diagnosis.Antibodyassay(EIA,IF,Westernblot).

Poxviruses

&Thevariolavirus,whichbelongstothegenusOrthopoxvirusandisthe

causativeagentinsmallpox,wasdeclarederadicatedin 1980 afteraWHO

vaccinationcampaign.Thevacciniavirus,usedattheendofthe 18 thcentury

byE.JennerinEnglandasavaccinevirustoprotectagainstsmallpox,isnow

usedasavectorinmolecularbiologyandasahybridviruswithdeterminants

fromothervirusesinexperimentalvaccines.Amongtheotherorthopox-

virusesfoundinanimals,themonkeypoxvirusesarethemainhumanpatho-

gens.Theanimalpathogensparapoxviruses(milker’snodules,orf)areocca-

sionallytransmittedtohumans,inwhomtheycauseharmlessexanthems.

Themolloscumcontagiosumvirusaffectsonlyhumansandcausesbenign

tumors.

Diagnosis. Orthopoxviruses and parapoxviruses: electron microscopy.

Molloscumcontagiosum:histology. &

Brick-ShapedOrthopoxvirus

1 00 nm

Fig.8. 7 Poxviruses measure

200 – 350 nm, putting them

justwithintheresolutionrange

oflightmicroscopes(TEM).

8

Kayser, Medical Microbiology © 2005 Thieme