Which species of plasmodium contains multiple rings in the infected RBCs?
Correct Answer: Plasmodium falciparum
Description: Ans. d (Plasmodium falciparum). (Ref. Harrison, Medicine, 18th/Table e27-l; Table 210-1).SpeciesDiseaseImportant featuresBlood smearsLiver stagesTreatmentPlasmodium vivaxBenign48-hour fever spikesEnlarged host cells, ameboid trophozoitesPersistent hypnozoites Relapse*Chloroquine PO4, then primaquinePlasmodium ovaleBenign tertian48-hour fever spikesOval, jagged, infected RBCsPersistent Hypnozoites RelapseChloroquine PO4 then primaquinePlasmodium malariaeQuartan or malarial72-hours fever spikes, recrudescenceBar and band forms rosette schizontsNo persistent stageChloroquine PO4 (no radical cure necessary)Plasmodium falciparumMalignant tertianIrregular fever spikes; causes cerebral malariaMultiple ring forms, crescent-shaped gametesNo persistent stage*Chloroquine resistance a problemMorphologic Characteristics of Human Malaria Parasite P. falciparumP. vivax IP. ovaleP. malariaeAsexual parasitesUsually only fine blue ring forms (some resembling stereo headsets) are seen. Parasitemia level may exceed 2%.Irregular large, fairly thick rings become highly pleomorphic as the paraisite grows. Parasitemia level is low.Regular, dense ring enlarges to compact, blue, mature trophozoite (rectangular or band-form). Parasitemia level is low.Dense, thick rings mature to dense, round trophozoites. Parasitemia level is low.SchizontsRare in peripheral blood; 8-32 merozoites, dark brown-black pigmentCommon; 12-18 merozo ites, orange- brown pigmen t8-14 merozoites, brown or black pigment8-10 merozoites, dark brown or black pigmentGametocytesBanana-shaped; male: light blue; female: darker blue; a few scattered blue-black pigment granules in cytoplasmRound or oval; male: round, pale blue; female: oval, dark blue; triangular nucleus, a few Grange pigment granulesLarge, round, dense, and blue (like P. malariae), but prominent James's dots; brown pigmentLarge, oval; male: pale blue; female: dense blue; large black pigment granulesRBC changesRBCs are normal in size. As the parasite matures, the RBC cytoplasm becomes pale, the cells become crenated, and a few small red dots may appear over the cytoplasm (Maurer's clefts)RBCs nre enlarged. Pale red Schuffner's dots increase in number as the paras ite matures.RBCs become oval with tufted ends. Red James's dots are prominent.RBCs are normal in size and shape. No red dots are seen.Characteristics of Plasmodium Species Infecting Humans FeaturesFalciparumVilpaxOvaleMalariae1Duration of intra lag phase5.5 days89152No. of Merozoites/ infection3300010,00015,00015,0003Duration of erythrocytic cycles484850724Red cell preferenceYounger cellsOlder RBC upto 14 daysReticulocytes,Older RBC's5MorphologyRing forms, banana gam etocytes & trophozoitesIrregular large rings & trophozoites Enlarged RBCs; S chuffner's dotsInfected RBCs enlarged & oval tufted ends; schuffner's dotsBand or rectangular forms of tropho-zoites6Pigment colourBlackYellowBrownDark brown7Ability to cause relapseNoyesYesNo
Category:
Microbiology
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