<prompt> 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 isPlasmodium falciparumPlasmodium vivaxPlasmodium malariaePlasmodium ovale  <response>: Ans. is b i.e., Plasmodium vivax Ref : Harrisons 17the p 1280 16e, p. 1219, 15e, p1204In 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 14-20P ovale- Dark brownP. ovale- Fewer than 12 6-12P. malariae- Brown blackP. malariae- Fewer than 12 6-12P. falciparum --- BlackP. falciparum- usually more than 12 merozoites8-32 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 malariaR malariae Quartan malariaP. falciparum Malignant tertianP. ovale Ovale malariaDuration of erythrocytic cycle hrs48124848Red cell preferenceReticulocytesOlder cellsYounger cellsReticulocytesDistribution in peripheral bloodAll formsAll formsOnly rings crescents gametocytes All formsParasitized Red Cells Enlarged, pale fine stippling Schuffner,s dotsNot enlarged No stippling Ziemanns dotsNot enlarged coarse stippling Maurers cleftsEnlarged pale Schuffners dotscells often fimbriated or crenatedLevel of Parasitemia2 upto 30,000 micron of blood210,000micron micronCan be 2 Sometimes very high level of parasitemia may exceed 200,000 micron commonly 50.000 micron 2 10,000micronPigmentsYellow brownBrown blackBlackDark brownOld trophozoitesVery pleomorphicOccasional band formCompact and roundedCompact and roundedGametocytesRound or ovalRound or ovalCrescentic banana shapedRound or ovalNo. of Merozoites in mature schizont14-24 in irregular clusters12 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 primaquineAbsent AbsentPresentRecrudescence Persistent red cell forms may lead to recrud escence upto 30 years later Incubation period14 days30 days12 days14 days 