Classification: Taxonomic ranks under review (cf. · Parasite morphology: Malarial parasites form four developmental stages in humans (hepatic schizonts and then ... Plasmodium Classification:Taxonomicranksunderreview(cf.IllustratedGuidetoProtozoa,2000.AllenPress)Protista(unicellulareukaryotes)Apicomplexa(cellswithclusteroforganellesknownasapicalcomplex)Haematozoea(vector-borneparasitesinfectingbloodcellsofvertebrates)Haemosporidia(blood-dwellingspore-formers,insectvectors)Family:PlasmodidaeTheseparasitesaretransmittedtovertebratehostsbyinsect(notablymosquito)vectors.Invertebrates,theyformamorphousdevelopmentalstages(plasmodia)inbloodcells(mostlyerythrocytes).Allstageshaveareducedapicalcomplex(lackingaconoid).Hundredsofspecieshavebeendescribedinmammals,birdsandreptiles;mostcausingnoapparentharmbutthoseinfectinghumanscausingoneoftheworstfeverscourgesofmankind,malaria.Parasitesundergoexoerythrocyticschizogonyinhepatocytesofvertebratesthenrepeatedcyclesofintraerythrocyticschizogonywithsomestagessubsequentlyundergoinggametogony.Manyspeciesproducehaemozoinpigmentgranulesasabyproductofhaemoglobinmetabolism.Gametesingestedbyinsectvectorsundergofertilizationinthegutformingmotilezygotes(ookinetes)whichformoocystsontheoutergutwall.Theoocystsproducethousandsofsporozoiteswhichinfectthesalivaryglandsandareinjectedintovertebratehostsduringfeeding.Plasmodiumspp.[thesespeciescausemalariainhumans]Parasitemorphology:Malarialparasitesformfourdevelopmentalstagesinhumans(hepaticschizontsandthenintraerythrocytictrophozoites,schizontsandgamonts)andthreedevelopmentalstagesinmosquitoes(ookinetes,oocystsandsporozoites).Liverschizontsappearasclustersofsmallbasophilicbodies(merozoitenuclei)locatedwithinhosthepatocytes,measuring40-80µmindiameterwhenmature.Intraerythrocyticstagesconsistofsmallroundedtrophozoites(ringforms)measuring1-2µmindiameter,amorphousmultinucleateschizontsmeasuringupto7-8µminlength,andmicro–(♂)andmacro-(♀)gametocytesranginginlengthfrom7-14µm.Themorphologicalcharacteristics(s