Malaria is a life-threatening protozoal vector-borne infection caused by Plasmodium parasites. It is transmitted to humans through the bites of infected female Anopheles mosquitoes. Once injected, parasites infect liver cells and red blood cells (erythrocytes).
Plasmodium Parasite Species
- Plasmodium falciparum: The most dangerous species; responsible for severe, fatal complications, cerebral malaria, and organ failure.
- Plasmodium vivax: Common cause of malaria; forms dormant liver hypnozoites causing recurrent relapses.
- Plasmodium ovale: Causes relapsing tertian malaria via liver hypnozoites.
- Plasmodium malariae: Causes quartan fever cycles and chronic low-grade nephrotic syndrome.
- Plasmodium knowlesi: Zoonotic primate malaria found in Southeast Asia, causing severe rapid parasitemia.
Symptoms (Appears 10–15 Days Post-Bite)
- Paroxysmal Cyclical Fevers: High fevers occurring every 48 hours (vivax/falciparum) or 72 hours (malariae).
- Rigors & Sweating: Severe cold shivering chills followed by high fever spikes and drenching sweats.
- Systemic Symptoms: Intense headache, muscle (myalgia) & joint pain, persistent nausea, vomiting, fatigue, and jaundice (yellow skin/eyes from hemolysis).
Severe Malaria Complications (Medical Emergency)
- Cerebral Malaria: Parasitized RBC sequestration in brain capillaries causing altered consciousness, seizures, and coma.
- Severe Anemia: Massive erythrocyte destruction by parasites.
- Acute Kidney Injury & Blackwater Fever: Hemoglobinuria (dark red urine) and renal failure.
- Acute Respiratory Distress Syndrome (ARDS): Fluid accumulation in lungs.
- Septic Shock & Multiorgan Failure: Profound hypotension and lactic acidosis.
Diagnostic Testing
- Giemsa-Stained Peripheral Blood Smear Microscopy: Gold standard; thick smear for parasite detection, thin smear for species identification.
- Rapid Diagnostic Tests (RDTs): Antigen-based tests detecting PfHRP2 or Plasmodium LDH.
- Polymerase Chain Reaction (PCR): Highly sensitive molecular confirmation for low parasitemia.
Treatment Guidelines
- Uncomplicated Malaria: Artemisinin-based Combination Therapies (ACTs such as Artemether-Lumefantrine or Artesunate-Amodiaquine). Chloroquine for sensitive P. vivax/ovale plus Primaquine/Tafenoquine for liver hypnozoite radical cure.
- Severe Malaria: Immediate IV Artesunate (or IV Quinine) administered in ICU, followed by full oral ACT course and supportive blood transfusions/dialysis.
Prevention Strategies
- Mosquito Control: Insecticide-Treated Nets (ITNs), indoor residual spraying, and eliminating stagnant water breeding sites.
- Chemoprophylaxis for Travelers: Doxycycline, Mefloquine, or Atovaquone-Proguanil taken before entering endemic areas.
- Malaria Vaccines: RTS,S/AS01 (Mosquirix) and R21/Matrix-M vaccines approved for pediatric prevention in endemic zones.
