A 35 year old male suffering from sudden onset of high grade fever. On malarial slide examination, all stages of the parasite are seen with schizonts of 20 microns size with 14-20 merozites per cell and yellow brown pigment. The diagnosis is
Ans. is 'b' i.e., Plasmodium vivax [Ref : Harrisons 17th/e p 1280 (16/e, p. 1219, 15/e, p1204)[In this question the species of malaria is recognized on the basis of two features:Colour of pigment &No. of merozoites per RBCs (in mature schizont).Colour of pigment No. of merozoites per schizontsP. vivax- Yellow brownP. vivax- More than 12 merozoites ( 14-20)P ovale- Dark brownP. ovale- Fewer than 12 (6-12)P. malariae- Brown blackP. malariae- Fewer than 12 (6-12)P. falciparum --- BlackP. falciparum- usually more than 12 merozoites(8-32) very rare in peripheral blood*.* To solve this question this much knowledge is sufficient but since malaria is a very important topic so one must be well versed with it.Some characteristic features of the malarial parasite of humanFeaturesP. vivax (Benign tertian malaria)R malariae (Quartan malaria)P. falciparum (Malignant tertian)P. ovale (Ovale malaria)Duration of erythrocytic cycle (hrs)*48*12*48*48*Red cell preference*ReticulocytesOlder cellsYounger cells*ReticulocytesDistribution in peripheral blood*All formsAll formsOnly rings & crescents (gametocytes)* All formsParasitized Red Cells *Enlarged, pale fine stippling (Schuffner,s dots)*Not enlarged No stippling (Ziemann's dots)*Not enlarged coarse stippling (Maurers clefts)*Enlarged pale (Schuffner's dots)*cells often fimbriated or crenatedLevel of Parasitemia<2% upto 30,000 /micron of blood<2%<10,000/micron /micronCan be >2%* Sometimes very high level of parasitemia may exceed 200,000 /micron commonly 50.000 / micron* <2%* <10,000/micronPigments*Yellow brownBrown blackBlackDark brownOld trophozoites*Very pleomorphicOccasional band form*Compact and roundedCompact and roundedGametocytesRound or ovalRound or ovalCrescentic banana shaped*Round or ovalNo. of Merozoites in mature schizont*14-24 in irregular clusters<12 large merozoites in rosettes18-32 (very rare in peripheral blood) in grape like clusters.<12 in rosetteHypnozoite (sleeping forms can remain quiescent for years ) *Present*( responsible for relapse, if not treated with primaquine)Absent *Absent*Present*Recrudescence Persistent red cell forms may lead to recrud escence upto 30 years later* Incubation period14 days*30 days*12 days*14 days*
Plasmodium falciparum
Plasmodium vivax
Plasmodium malariae
Plasmodium ovale
Malaria