Malaria
Download as PPT, PDF9 likes778 views
This document summarizes malaria, including its causative agents, transmission, distribution, pathology, clinical features, complications, diagnosis, management, prevention, and control. Malaria is transmitted by mosquitoes and causes millions of deaths each year, mostly in children in Africa. Plasmodium falciparum is the most dangerous malaria parasite and can cause severe complications including cerebral malaria, if not promptly treated. Diagnosis involves examining blood films for malaria parasites. Treatment depends on the malaria species and severity, ranging from chloroquine for non-falciparum malaria to quinine or artemisinin combinations for falciparum malaria. Prevention focuses on avoiding mosquito bites through protective clothing, repellents, and insecticide
Malaria
- 2. Malaria • Agent – Plasmodium falciparum – P. vivax – P. ovale – P. malariae • Transmission-by the bite of female anopheles mosquitoes • Occurs throughout the tropics and subtropics at altitudes below 1500 meters
- 5. Drug resistant Malaria Red - chloroquine resistant Green - chloroquine sensitive Black - chloroquine and mefloquine resistant
- 8. 3 million deaths/yr. 1 million in Africa, mostly children below the age of 5
- 9. Pathology • Hemolysis of infected red cells and adherence of infected cell to capillary wall • Hemolytic anaemia • dyserythropoiesis, • splenomegaly • depletion of folate stores • P. vivax and P. ovale invade reticulocytes • P. malariae normoblastsmost • P. falciparum • invades red cells of all ages but especially young cells • red cells containing schizonts adhere to capillary endothelium in brain, kidney, liver, lungs and gut • Malaria immune population • haemoglobin F, C or especially S –falciparum • lack the Duffy blood group – ovale
- 10. Pathology
- 11. Pathology
- 12. Electronmicroscope view of gut of mosquito
- 13. Life cycle of malaria parasite • Female anopheles feed on human blood containing gametocytes (Sexual form) • Complete sexual cycle in mosquito in 7-10 days and become sporozoites • Sporozoites inoculated by bite of infected mosquito • Sporozoites leave the blood stream and enter into the hepatocyte within half and hour • Hepatocytes brust after few days and release merozoites • Merozoites enter into RBCs and multiplication to complete the asexual life cycle • Merozoites develop into schizont in RBC and release more merozoites in the blood and peak fever coincide to this time • Ovale and vivex may persist in liver cells as dermant forms called hypnozoites and capable of producing merozoites months or years later
- 14. Incubation period and fever P. vivax/ P. ovale 8-25 days / Tertian P. malariae 15-30 days / Quartan P. falciparum 8-25 days / Aperiodic
- 15. Clinical features • P. vivax and P. ovale • Fever with a rigor • Feeling of cold • Development of high fever • Hot or flush phage • Profuse sweating and gradual fall in fever • Cycle is repeated 48 hours later • Spleen and liver enlarge • Anaemia • Frequent Relapses in the 1st 2 years
- 16. Clinical features P. malariae Mild symptoms Bouts of fever every third day. Parasitaemia may persist for many years with recrudescence of fever, or without producing any symptoms Causes glomerulonephritis and the nephrotic syndrome in children
- 17. P. FALCIPARUM • Most dangerous of the malarias • Onset -insidious, with malaise, headache and vomiting, and is often mistaken for influenza. • Cough and mild diarrhoea are also common. • The fever has no particular pattern. • Jaundice is common due to haemolysis and hepatic dysfunction. • The liver and spleen enlarge and become tender. • Anaemia develops rapidly. • Develop dangerous complications
- 18. P Falciparum
- 19. Complications of falciparum malaria Unarousable coma/ convulsion /cerebral malaria Acidemia/acidosis -Arterial pH <7.25 or plasma bicarbonate level of <15 mmol/L Severe normochromic, normocytic anemia Renal failure -Urine output (24 h) of <400 mL in adults or <12 mL/kg in children
- 20. Complications of falciparum malaria Pulmonary edema Noncardiogenic pulmonary edema/adult respiratory distress syndrome Hypoglycemia Hypotension/shock Bleeding/disseminated intravascular coagulation Hemoglobinuria / Macroscopic black, brown, or red urine
- 21. Cerebral malaria • Severe form of malaria • Coma is a characteristic and ominous feature • Despite treatment, is associated with death rates of ~20% among adults and 15% among children. • Diffuse symmetric manifestation of encephalopathy • Focal neurology unusal
- 22. Cerebral malaria • No signs of meningeal irritation but resistant to passive neck flexion • Tonic clonic convulsions • Deep coma • Patient recovering may develop sequale( <3% in adult and about 15% in child) • Hemiplesia • Cerebral palsy • Cortical blindness • Deafness • Cognitive and learning defect
- 23. Features indicating poor prognosis in falciparum malaria Clinical Parameter Marked agitation Hyperventilation (respiratory distress) Hypothermia (<36.5°C) Bleeding Deep coma Repeated convulsions Anuria Shock
- 24. Laboratory parameter Biochemistry Hypoglycemia (<2.2 mmol/L) Hyperlactatemia (>5 mmol/L) Acidosis (arterial pH <7.3, HCO3 <15 mmol/L) Elevated serum creatinine (>265 mol/L) Elevated total bilirubin (>50 mol/L) Elevated liver enzymes (AST/ALT X 3 times ) Elevated muscle enzymes (CPK , myoglobin ) Elevated urate (>600 mol/L)
- 25. Laboratory parameter Hematology Leukocytosis (>12,000/L) Severe anemia (PCV <15%) Coagulopathy Decreased platelet count (<50,000/L) Prolonged prothrombin time (>3 s) Prolonged partial thromboplastin time Decreased fibrinogen (<200 mg/dL)
- 27. Diagnosis • Thick blood film • Low parasitemia- thick film erythrocytes are lysed, releasing all blood stages of the parasite • Thin film • confirm the diagnosis, • to identify the species of parasite • P. falciparum, only ring forms • Immunochromatographic 'dipstick' tests or plasmodium LDH test
- 28. Management • P. vivax, P. ovale and P. malariae • Chloroquine: 600 mg chloroquine base followed by 300 mg base in 6 hours, then 150 mg base 12-hourly for 2 more days • Mild falciparum malaria • Quinine dihydrochloride or sulphate drug of choice -600 mg salt (10 mg/kg) 8-hourly by mouth is given until the patient is clinically better ,followed by a single dose of sulfadoxine 1.5 g combined with pyrimethamine 75 mg, i.e. 3 tablets of Fansidar
- 29. Management of mild falciparum • Sulphonamide sensitivity • quinine may be followed by doxycycline 100 mg daily for 7 days • Atovaquone 250 mg plus proguanil 100 mg (Malarone) • 4 tablets once daily for 3 days • Artemether plus Mefloquine • Artemether 200 mg/day orally for 5 days then mefloquine 500 mg in 2 doses 2 hours apart • Pregnancy a 7-day course of quinine alone
- 30. Management of severe malaria • Early and appropriate antimalarial drugs • Active treatment of complications • Correction of fluid, electrolyte • Acid-base balance • Avoid hypoglycemia • Avoidance of harmful ancillary treatments
- 31. Radical cure of malaria • P. vivax and P. ovale • Primaquine (15 mg daily for 14 days) • Destroys the hypnozoite phase in the liver • S/E- • Haemolysis (G6PD)-deficient • Cyanosis due to the formation of methaemoglobin
- 32. Chemoprophylaxis of malaria • Chloroquine resistance high • Mefloquine 250 mg once weekly • Doxycycline 100 mg daily • Malarone 100 mg daily • 1 tablet from 1-2 days before travelling to 1 week after return • Chloroquine resistance moderate • Chloroquine plus Proguanil 150 mg base+100 mg (Two tablets weekly+Two tablets daily ) • Chloroquine resistance absent • Chloroquine or Proguanil 150 mg base or 100 mg (Two tablets weekly/One or two tablets daily)
- 33. Malaria control in endemic areas • Sanitation and improvement in living condition • Avoid mosquito bites • Permethrin-impregnated bed nets • DDT and insecticide spray • Malaria vaccine under evaluation, in Thailand and Africa
- 34. Prevention
- 35. Prevention
- 36. Personal protection against malaria • Avoidance of exposure to mosquitoes at their peak feeding times (usually dusk and dawn) and throughout the night • Insect repellents creams • Suitable clothing – full sleeve • Widespread use of insecticide-impregnated bed nets or other materials