Black water fever – Basic microbiology, parasitology, and immunology; nature, reproduction, growth, and transmission of common microorganisms and parasites in Bangladesh; prevention including universal precaution and immunization, control, sterilization, and disinfection; and specimen collections and examination. Students will have an understanding of common organisms and parasites caused human diseases and acquire knowledge about the prevention and control of those organisms.
Black Water Fever:
Definition: It is a manifestation of falciparum malaria occurring in previously infected subjects and is characterized by sudden intravascular haemolysis followed by fever and haemoglobinuria.
Etiology; It is associated with infection by P. falciparaum, most commonly observed among the non- immune individuals who have resided in endemic zone for 6 months to 1 year and have had inadequate doses of quinine for both prophylaxis and treatment.
Pathogenesis: Intravascular haemolysis.
Mechanism:
Extensive intravascular haemolysis
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Breakdown of RBC and excessive release of Hb in blood
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Saturation of haptoglobin (Hb binds with haptoglobin)
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Free Hb (unable to bind)
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Clinical manifestation
Pathology:
➤ Kidney:
- Large and dark in colour.
- Degenerative changes in DCT and blocked with Hb casts.
➤ Liver: Enlarged, soft and stained intensely yellow.
➤ Gall bladder:
- Filled with dark green viscid bile
➤ Spleen: Enlarged.
Clinical features:
- Fever and rigor, followed by aching pains in the loins.
- Haemoglobinuria.
- Icterus.
- Bilious vomiting.
- Circulatory collapse
- Acute renal failure.
Complications:
- Renal failure (uremia).
- Acute liver failure.
- Circulatory collapse
Pathogenesis of Cerebral Malaria:
P. falciparum infection
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Increase stickiness and adhesiveness of RBC through circulation in capillary of brain (coated with firbrin)
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Clumping of parasitized RBC
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Micro-thrombus formation
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Blockage of capillary blood vessels of brain
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Ischaemia
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Hypoxiai
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Necrosis, hemorrhage and edema in brain
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Loss of consciousness.
Causes of Anaemia in Malaria:
- Mechanical lysis of infected RBC (Haemolysis).
- Immune mediated lysis of both normal and infected RBC due to production of antibody against RBC (Autoimmune haemolytic anaemia)
- Splenomegaly causes RBC sequestration and lysis
- Dyserythropoiesis due to affected bone marrow.
- Depletion of folic acid.
- Phagocytosis of uninfected erythrocytes.
- Antimalarial drug (primaquine) in gluose-6-phosphate dehydrogenase deficiency.
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