Malaria ppt deepa babin

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  • 1. DEEPA BABINASST PROF,MICROBIOLOGY,TMC
  • 2. Malaria is a major public healthproblem in warm climates especiallyin developing countries.It is a leading cause of disease anddeath among children under fiveyears, pregnant women and non-immune travellers/immigrants.Malaria
  • 3. Name means bad air- A life-threatening parasitic disease 40% of the worlds population is at risk 90% of the deaths due to Malaria occur in Sub-Sahara Africa, mostly among young children. Around 400-900 million people are affected At least 2.7 million deaths annually.
  • 4. What is malaria ?Malaria is a disease caused by the protozoan parasites of the genus Plasmodium.The 4 species that commonly infect man are:Consists of 4 species:P. vivaxP. falciparumP. malariaeP. ovale Plasmodium parasites are highly specific with female Anophelesmosquitoes
  • 5. Benign tertian malaria = Vivax MalariaMalignant tertian Malaria = Falciparum MalariaQuartian Malaria = P.MalariaOvale malaria -P. ovale
  • 6. Landmarks in the evolution of Malaria 1880 Laveran identified the malarial parasite inan unstained smear 1885 Golgi described the blood stage(erythrocytic schizogony) of malarial parasite Golgi cycle 1898 Amigo & Grassi described the life cycle 1891 Romanowsky introduced the stainingmethod 1897 Ronald Ross while in Calcutta, India,demonstrated Anopheles sp. of mosquitoes asvectors of malaria.Got Nobel prize for his work in 1902
  • 7. 26/04/07Transmission & Life CycleDefinitive host Female Anopheles mosquitoIntermediate host ManInfective form SporozoitesPortal of entry SkinMode of transmission Bite of an infected mosquitoSite of localization First in liver cells & then inRBCs
  • 8. Malaria parasites are transmitted from oneperson to another by the bite of a femaleanopheles mosquito. The female mosquito bites during dusk and dawnand needs a blood meal to feed her eggs. Male mosquitoes do not transmit malaria as theyfeed on plant juices and not blood. There are about 60 species of anopheles are ableto transmit malaria. Like all mosquitoes, anopheles breed in water -hence accumulation of water favours the spreadof the disease.
  • 9. 26/04/07Incubation period P. vivax P. ovale 10 to 14 days P. falciparum P. malariae 18 days to 6weeks
  • 10. Infection SporozoitesLiverAsexualcycleG ametocytesMerozoitesTransmissionto mosquitoClick on thediagram to exploredifferent areas ofthe life cycle
  • 11. 26/04/07Clinical Features Series of febrile paroxysms fever is causedby the release of merozoites & toxins fromruptured erythrocytic schizont which in turncauses the release of cytokines.Quartan malaria every 72 hrsTertian malaria - every 48 hrs* each paroxysm has 3 stages - cold stage(rigors), hot stage (high temp., body & jointpains, vomiting & diarrhoea) andperspiration stage (fall in temp.)
  • 12. Erythrocytic schizogony is thetime taken for trophozoites tomature into merozoites beforerelease when the cell ruptures.It is shortest in P. falciparum (36hours), intermediate in P. vivaxand P. ovale (48 hours) andlongest in P. malariae (76hours).Note how the frequency of spikes of fever differ accordingto the Plasmodium species. In practice, spikes of fever inP. falciparum, occur irregularly - probably because of thepresence of parasites at various stages of development.
  • 13. o Vomitingo Diarrhoea more commonly seen in young children and, when vomiting also occurs, may be misdiagnosed asviral gastroenteritiso Convulsions commonly seen in young children. Malaria is the leading cause of convulsions with fever in Africanchildren.o Pallor resulting mainly from the lysis of red blood cells. Malaria also reduces the synthesis of red blood cells inthe bone marrow.o Jaundice mainly due to haemolysis.Malaria is a multisystem disease. Other common clinical features are:o Anorexiao Cougho Headacheo Malaiseo Muscle acheso Splenomegalyo Tender hepatomegalyThese clinical features occur in mild malaria. However, the infection requires urgent diagnosis andmanagement to prevent progression to severe disease.
  • 14. 26/04/07Falciparum Malaria Most widespread Accounts for 80% of malaria cases worldwide Most pathogenic of human malaria species Untreated infections - severe disease & evendeath, particularly in young children, pregnantwoman & non immune adults.
  • 15. 1. Cerebral malaria2. Severe malaria anaemia3. Hypoglycaemia4. Metabolic acidosis5. Acute renal failure6. Pulmonary oedema7. Circulatory collapse, shock oralgid malaria8. Blackwater feverNearly all severe disease and the estimated >1 million deaths from malariaare due to P. falciparum. Although severe malaria is both preventable andtreatable, it is frequently a fatal disease.The following are 8 important severe manifestations of malaria:Click on each severe manifestation for detailsNote: It is common for an individual patient to have more thanone severe manifestation of malaria!
  • 16. 26/04/07Pernicious Malaria Def: refers to a series of phenomenon occurringduring infection with P. falciparum which, if noteffectively treated, threatens the life of the patientwith in 1 to 3 days In children & non immune adults, can cause coma &death Cerebral malaria. Occurs as a result of capillary blockage.
  • 17. 26/04/07Anaemia Can be severe & occur rapidly, particularly inyoung children Occurs due to destruction of parasitised RBCs phagocytosis & destruction in the spleen Decreased production of RBCs in the bonemarrow.
  • 18. 26/04/07Black Water Fever Occurs in previously infected subjects Can also occur in non immune adults with severefalciparum malaria, and also as a complication ofquinine therapy. A rare but acute condition characterised by sudden& massive hemolysis of parasitised & nonparasitised RBCs followed by fever andhaemoglobinuria. Often fatal due to renal failure
  • 19. 26/04/07Black Water Fever Difficult to find the parasitesin the blood following ahemolytic attack. Urine appears dark red tobrown black due to thepresence of free Hb. Clinical features fever, rigor, aching pains in the loin,icterus, bilious vomiting, circulatory collapse,haemoglobinuria & acute renal failure. Treatment Chloroquine, blood transfusion, peritonealdialysis in ARF.
  • 20. 26/04/07Recurrence of Malaria Two types of recurrences known in malaria:1. Recrudescence seen in P. falciparum & P. malariae due to persistence of blood infection (some erythrocyticforms evade host immunity) even after clinical illness hassubsided. The numbers may increase later, leading to reappearanceof clinical symptoms Occur mostly up to one year or so but in P. malariae, itcan occur even after decades
  • 21. 26/04/07Recurrence of Malaria2. Relapse Occurs due to a special form of parasites hypnozoites. Hypnozoites are the sporozoites that remaindormant after infecting liver Activated from time to time to initiate preerythrocytic schizogony - Exoerythrocyticschizogony
  • 22.