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Malaria Species
• Four species of malaria :
– Plasmodium falciparum: malignant tertian malaria
– Plasmodium vivax: benign tertian malaria– Plasmodium ovale : benign tertian malaria– Plasmodium malariae: quartan malaria
Estimated incidence malaria episodes(caused by any species)
resulting from local transmission, country level averages, 2004
Exo-erythrocytic (hepatic) cycle
Hypnozoites
Sporozoites
Salivary Gland
LIFE CYCLE OF MALARIALIFE CYCLE OF MALARIA
Gametocytes
Erythrocytic Cycle
Zygote
Oocyst
Stomach Wall
Pre-erythrocytic (hepatic) cycle
sporozoites
Components of the Malaria Life CycleComponents of the Malaria Life Cycle
Mosquito Vector
Human Host
Sporogonic cycle
Infective Period
Mosquito bitesgametocytemic person
Mosquito bitesuninfected person
PrepatentPeriod
Incubation Period
Clinical Illness
Parasites visible
Recovery
Symptom onset
Chronic Disease
Chronic Asymptomatic
Infection
PlacentalMalariaAnemia
InfectionDuring
Pregnancy
Developmental Disorders;
Transfusions;Death
LowBirth weight
IncreasedInfant
Mortality
Acute DiseaseAcute Disease
Non-severeAcute Febrile
disease
CerebralMalaria
Death
CLINICAL PICTURECLINICAL PICTURE
Uncomplicated malaria
• Uncomplicated malaria is defined as: Symptomatic infection with malaria parasitemia without signs of severity and/or evidence of vital organ dysfunction .
Malarial Paroxysm
cold stage•feeling of intense cold •vigorous shivering •lasts 15-60 minutes
hot stage •intense heat •dry burning skin •throbbing headache •lasts 2-6 hours
sweating stage •profuse sweating •declining temperature •exhausted and weak → sleep •lasts 2-4 hours
Severe malaria • Severe malaria is defined as symptomatic malaria in a patient with P. falciparum
asexual parasitaemia with one or more of the following complications:– Cerebral malaria (unrousable coma not attributable to other causes). – Generalised convulsions (> 2 episodes within 24 hours) – Severe normocytic anaemia (Ht<15% or Hb < 5 g/dl)– Hypoglycaemia (glood glucose < 2.2 mmol/l or 40 mg/dl )– Metabolic acidosis with respiratory distress (arterial pH < 7.35 or bicarbonate < 15
mmol/l) – Fluid and electrolyte disturbances– Acute renal failure (urine <400 ml/24 h in adults; 12 ml/kg/24 h in children) – Acute pulmonary oedema and adult respiratory distress syndrome– Abnormal bleeding– Jaundice– Haemoglobinuria– Circulatory collapse, shock, septicaema (algid malaria)– Hyperparasitaemia (>10% in non-immune; >20% in semi-immune)
Child with severe malaria anaemia and no other malaria complication
Complications of malaria :
anaemia
Clinical Picture :
Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency may develop intravascular haemolysis and haemoglobinuria precipitated by primaquine and other oxidant drugs, even in the absence of malaria. Haemoglobinuria associated with malaria (“blackwater fever”) is uncommon and malarial haemoglobinuria usually presents in adults as severe disease with anaemia and renal failure.
Malarial haemoglobinuria
CCMOVBD Plasmodium falciparum CCMOVBD Plasmodium vivax
CCMOVBD Plasmodium malariae Malaria Tutorials, Wellcome Trust Plasmodium ovale
Laboratory diagnosis of malariaLaboratory diagnosis of malaria
Features of Plasmodium
CCMOVBD
Nucleus/chromatin dot
Cytoplasm
Stippling
Vacuole
Laboratory diagnosis of malaria
3. Gametocyte
The Malaria Parasite
Three developmental
stages seen in blood
films:
1. Trophozoite
2. Schizont
CCMOVBD CCMOVBD
Trophozoites
CCMOVBD
GametocyteSchizont
CCMOVBD
Laboratory diagnosis of malaria
Plasmodium falciparum (trophozoite stage)
Diagnostic Points:• Small, regular, fine to fleshy
cytoplasm• Infected RBCs not enlarged• Numerous, multiple infection
is common• Ring, comma, marginal or
accole forms are seen; often have double chromatin dots
• Maurer’s dots not clearly visible
CCMOVBD
Multiple infection
Double chromatin
Marginal form
Laboratory diagnosis of malaria
Plasmodium facliparum
Laboratory diagnosis of malaria
Rapid diagnostic tests detect malaria antigens
Laboratory diagnosis of malaria
ACTION OF ANTIMALARIAL DRUG IN THE DIFFERENT LIFE ACTION OF ANTIMALARIAL DRUG IN THE DIFFERENT LIFE STAGES OF THE MALARIA PARASITESTAGES OF THE MALARIA PARASITE
Wellcome Trust (Modified)
Tissue SchizontocidesTissue Schizontocides•PrimaquinePrimaquine•PyrimethaminePyrimethamine•TetracyclineTetracycline•ProguanilProguanil
Anti-relapse (P.vivax)•primaquine
Blood Schizontocides•Chloroquine•Sulfadoxine/Pyrimethamine•Quinine•Quinidine•Artemisinins
GametocyideGametocyidePrimaquinePrimaquine
SporontocidesSporontocides•PrimaquinePrimaquine•PyrimethaminePyrimethamine•ProguanilProguanil
Main Malaria Control Measures
1. Early diagnosis and treatment of cases
2. Vector control : • adult mosquitoes :insecticides • mosquito larvae: draining
breeding sites 3. Reducing vector-human contact: bed nets
, repellents
4. Early detection and control of epidemics
Recommended