Medical Microbiology

Leptospira(Leptospirosis,WeilDisease) 329

damagemainlytheendothelialcellsofthecapillaries,leadingtogreaterper-

meabilityandhemorrhageandinterruptingtheO 2 supplytothetissues.

Jaundiceiscausedbyanonnecrotichepatocellulardysfunction.Disturbances

ofrenalfunctionresultfromhypoxictubulardamage.Aclinicaldistinctionis

drawnbetweenanictericleptospirosis,whichhasamildercourse,andthe

severeclinicalpictureofictericleptospirosis(Weildisease).Inprinciple,any

oftheserovarscouldpotentiallycauseeitherofthesetwoclinicalcourses.In

practice,however,theserogroupicterohemorrhagiaeisisolatedmorefre-

quentlyinWeildisease.

Bothtypesofleptospirosisarecharacterizedbyfeverwithchills,head-

ache,andmyalgiasthatsetinafteranincubationperiodofsevento 12

days.Thisinitialsepticstageofthediseaselaststhreetosevendaysand

isthenfollowedbythesecond,so-calledimmunestage,whichlastsfrom

fourto 30 days.Themostimportantclinicalmanifestationofstagetwoan-

ictericleptospirosisisamild,asepticmeningitis.ThesecondstageofWeil

diseaseischaracterizedbyhepaticandrenaldysfunctions,extensivehemor-

rhaging,cardiovascularsymptoms,andcloudingofthestateofconscious-

ness.Theimmunityconferredbysurvivaloftheinfectionisreliable,but

onlyprotectsagainsttheonespecificserovar.

Diagnosis.Detectionandidentificationofleptospiraeareaccomplishedby

growingtheorganismsincultures.Blood,cerebrospinalfluid,urine,ororgan

biopsies,whichmustnotbecontaminatedwithotherbacteria,areincubated

inspecialmediumsat 27 – 308 Cforthreetofourweeks.Amicroscopecheck

(darkfield)iscarriedouteveryweektoseeifanyleptospiraeareproliferating.

TheLeptospiraearetypedserologicallyinalysis-agglutinationreactionwith

specifictestsera.

Themethodofchoiceforalaboratorydiagnosisisanantibodyassay.

Theantibodiesproducedafterthefirstweekoftheinfectionaredetected

Leptospirainterrogans

Fig.4. 26 Serogroup

icterohemorrhagiae.

Culturepreparation.

Darkfieldmicroscopy.

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Kayser, Medical Microbiology © 2005 Thieme