Medical Microbiology

thatthemalignanttertianmalaria(malariatropica)oftendoesnotshowthis

typicalperiodicity.

&Classicmalarialparoxysm.Afteraninitialriseintemperaturetoabout

398 C,peripheralvasoconstrictioncausesaperiodofchills(lastingforabout

10 minutestoonehour),thenthetemperatureonceagainrisesto 40 – 418 C

(febrilestagetwotosixhours),whereuponperipheralvasodilatationandan

outbreakofsweatingfollow.Theseboutsoccurmainlyintheafternoonand

eveninghours.Oncetheparoxysmhasabatedandthefeverhasfallen,the

patientfeelswellagainuntilthenextonebegins.Inseveremalariatropica,

however,circulatorydisturbances,collapse,ordeliriummayoccurwithout

fever(algidmalaria).

&Courseofinfectionandrecurrence.Themalarialparoxysmsarere-

peatedatintervalsuntilparasitemultiplicationintheerythrocytesissup-

pressedbychemotherapyorthehostimmuneresponse.Parasitesthatpersist

inthehostcancauserelapsesformonthsorevenyearsaftertheinitialin-

fection.Recurrenceresultseitherfrompersistenceoferythrocyticforms(re-

crudescence)orreactivationofhypnozoites(p.522)(relapse).

Typesofmalaria

&Tertianmalaria(malariatertiana),causedbyP.vivaxorP.ovale:

Incubationperiod: nineto 20 days,alsoseveralweeksormonths.

Parasitemia: generallylowlevel,uptoamaximumof 1 – 2 %.

Course: usuallybenign(“benignmalaria”).Febrilestagethree

tofourhours,again 48 hourslater.Ifuntreated,dis-

easelaststhreetoeightweeksorlonger.

Recurrence: frequentrelapses,aftermonthsandforuptofive

years;

important:misdiagnosisisfrequent!

Specialcharacteristics: “tertianaquotidiana”ischaracterizedbydailybouts

offeverandresultswhentwoparasitepopulations

overlap.

&Quartanmalaria(malariaquartana),causedbyP.malariae:

Incubationperiod: 15 – 40 days(usuallylongerthanwithotherspecies).

Parasitemia: generallylowlevel,uptoamaximumof 1 %.

Course: usuallybenign.Febrilestagefourtofivehours,

again 72 hourslater.Ifuntreated,diseaselaststhree

to 24 weeksorlonger.

Recurrence: frequentrecrudescences, aftermonthsandeven

decades (30 years). Important: misdiagnosis is

frequent!

Specialcharacteristics: nephroticsyndrome,especiallyinAfricanchildren.

Plasmodium 527

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Kayser, Medical Microbiology © 2005 Thieme