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Parasitic protists of human importance :. Disease : Malaria Agent : Plasmodium 4 species Differential pathogenicity Vector-borne Apicomplexan inhabiting liver & blood. Global malaria mortality between 1980 and 2010: a systematic analysis. Murray et. al. 2012 Lancet vol 379, February 4 2012.
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Parasitic protists of human importance : Disease : Malaria Agent : Plasmodium 4 species Differential pathogenicity Vector-borne Apicomplexan inhabiting liver & blood
Global malaria mortality between 1980 and 2010:a systematic analysis Murray et. al. 2012 Lancet vol 379, February 4 2012 Key findings: Mortality burden higher in adults than previously estimated. Significant decline in mortality in Africa.
Malaria • Plasmodium vivax : Most predominant and only species which extends to temperate regions. Benign tertian. Relapses. • Plasmodium ovale : Tropical Africa, occasionally S. America and Asia. Ovale tertian. Relapses • Plasmodium malariae : Primarily subtropical. Less frequent. Quartan.
Malaria Plasmodium falciparum : Most pathogenic species. Entirely confined to tropics and subtropics. Clinically sharply differentiated from the other three species. Malignant tertian.
Malaria : diagnosis • Microscopy : Blood smears : thin versus thick smears • Differentiation from P. falciparum (medical emergency in non-immune) • Rapid diagnostic antigen test • Serology • Gene amplification methods
Complications • Cerebral malaria • Anemia • Renal disease • Blackwater fever • Dysenteric malaria • Algid malaria • Hyper-reactive malarial splenomegaly (HMS)
Pathogenesis • Sequestration + cytoadherence : stage & strain-specific parasite-derived ligands • Host secreted proteins : cytokines : TNF and interleukins • Differential ability to infect RBCs • RBC recognition and invasion • Paroxysm
Epidemiology • Transmission : characteristics of the vector • Other forms of transmission (blood transfusion, shared needles, congenital) • Innate resistance : red blood cell defects • Immunity • Control : eradication versus containment
Treatment : malaria • Management of severe falciparum malaria • Chloroquine-resistant P. falciparum • Chloroquine-sensitive P. falciparum or P. vivax, P. ovale and P. malariae • Severe falciparum chemotherapy • Chemotherapy for P. vivax and P. ovale • Chemotherapy for P. malariae
Prevention and Control • Malaria control strategy • Early diagnosis & treatment • Selective & sustainable prevention against parasite & vector • To detect & contain epidemics • To reassess regularly a country’s malaria situation • Roll back malaria campaign/WHO strategy • Note : impregnated bednets
Current leading recombinant pre-erythrocytic malaria vaccine candidate: RTS,S/AS01or AS02 (circumsporozoite protein) First results of Phase 3 Trial of RTS,S/AS01 malaria vaccine in African children The RTS,S Clinical Trials Partnership New England Journal of Medicine, November 17, 2011 vol 365, no. 20