Malaria

🌍 About

• 🦟 Malaria is a life-threatening disease caused by Plasmodium parasites, transmitted by infected female Anopheles mosquitoes.
• ⚡ Even when not fatal, malaria causes major debility, reducing productivity and quality of life.
• 👩‍🦱🧑 Predominantly affects working-aged adults → high socioeconomic burden.
• 🤒 Closely linked with poverty, high infant mortality, and chronic morbidity.
• 📖 See BNF for Current Treatment Guidelines

📜 Etymology

• The word "malaria" comes from Italian "mala aria" → “bad air,” from the ancient belief it arose from marsh vapours.

🧬 Types of Plasmodium

• ⚫ P. falciparum: Deadliest form, majority of severe disease & deaths, esp. Africa.
• 🟢 P. vivax: Relapses due to dormant hypnozoites, more common outside Africa.
• 🟣 P. ovale: Similar to vivax; forms hypnozoites → relapse risk.
• 🟡 P. malariae: Milder, but can persist for years → chronic infection.
• 🔴 P. knowlesi: Zoonotic (SE Asia); rapidly progressive, often misdiagnosed as P. malariae.

⚠️ Risk Factors

• 🧬 Sickle cell trait → partial protection vs P. falciparum.
• 🩸 Duffy-negative blood group → resistance to P. vivax (common in Africa).
• 🔄 Repeated infections → partial immunity but species/strain-specific.
• 👶 Infants & children → highest risk of severe disease.
• 🧍‍♂️ Adults returning to endemic areas lose immunity → vulnerable again.

⏳ Incubation Periods

• ⚫ P. falciparum: 10–14 days.
• 🟢 P. vivax / P. ovale: 10–14 days + months/years later relapse.
• 🟡 P. malariae: 18 days–6 weeks; can persist long-term.
• 🔴 P. knowlesi: 9–12 days.

🩺 Clinical Presentation

• 🌡️ Cyclical fever, chills, and sweats (classic paroxysms).
• 🤕 Headache, myalgia, nausea, vomiting, malaise.
• ⚫ P. falciparum: Severe complications → cerebral malaria, hypoglycaemia, anaemia, organ failure.
• 📈 Chronic infection → splenomegaly, anaemia, higher risk of coinfections.
• 👶 Neonates relatively protected in first 6 months (maternal antibodies + fetal Hb).

🔬 Investigations

• Microscopy:
  • 🧪 Thick film → sensitive for detection.
  • 🔍 Thin film (Giemsa) → species ID + parasitaemia quantification.
  • Repeat over 48 hrs if negative but suspicion high.
• 💡 RDTs: Detect antigens (useful without labs).
• 🧬 PCR: Species confirmation, low-level parasitaemia.
• 📊 Supportive: CBC (anaemia, thrombocytopenia), LFTs, RFTs, pregnancy test.

💊 Management

Depends on Plasmodium species, severity, and local resistance patterns.

🌿 Non-Falciparum Malaria

• 🟢 P. vivax, 🟣 P. ovale, 🟡 P. malariae, 🔴 P. knowlesi.
• 💊 Chloroquine (if no resistance).
• 🔄 ACTs (e.g. artemether-lumefantrine, atovaquone-proguanil) if chloroquine-resistant.
• 🌙 Primaquine for vivax/ovale radical cure (kills liver hypnozoites). ⚠️ Test for G6PD first!
• 🧴 Severe cases → IV artesunate or IV quinine.

⚫ Falciparum Malaria

• ⏱️ Medical emergency – rapid treatment needed.
• 💊 First-line: ACTs (artemether-lumefantrine, atovaquone-proguanil).
• 💉 Severe disease: IV artesunate preferred over quinine.
• 🛠️ Supportive: Correct hypoglycaemia, anaemia, seizures, renal failure.
• 🤰 Pregnancy → special drug regimens (see NICE/BNF guidance).

🛡️ Prevention

• 🛏️ Bed nets + 🏠 Indoor spraying + 🦟 source control.
• 💊 Chemoprophylaxis for travellers (per guidelines).
• 💉 Vaccination: RTS,S/AS01 in children in endemic regions.
• 👕🧴 Protective clothing + DEET repellents.

📌 Key Points

• ⏱️ Early diagnosis + treatment = prevents deaths & reduces transmission.
• ⚠️ Drug resistance rising → always follow updated guidance.
• 🔬 Ongoing research & public health measures are crucial for elimination goals.

Cases - Malaria

• Case 1 - Severe falciparum malaria 🌍: A 27-year-old man returns from Nigeria with 3 days of fever, rigors, and confusion. Exam: jaundice, splenomegaly, GCS 12/15. Bloods: Hb 8.5 g/dL, platelets 40 ×10⁹/L, creatinine 280 µmol/L. Blood film: Plasmodium falciparum parasitaemia 8%. Diagnosis: severe falciparum malaria. Managed with IV artesunate, ICU support, and careful fluid balance.
• Case 2 - Relapsing malaria 🔄: A 32-year-old woman returns from India with intermittent fevers every 48 hours, sweats, and malaise. Thick/thin films: Plasmodium vivax. Exam: splenomegaly, mild anaemia. Diagnosis: vivax malaria. Managed with chloroquine for acute episode, followed by primaquine to eradicate hypnozoites in the liver.
• Case 3 - Imported uncomplicated malaria ✈️: A 19-year-old student presents with fever, myalgia, and diarrhoea after a gap year in Ghana. She did not take prophylaxis. Blood film: ring forms of Plasmodium falciparum, parasitaemia 0.8%. Diagnosis: uncomplicated falciparum malaria. Managed with oral artemisinin-based combination therapy (e.g. artemether-lumefantrine) and supportive care.

Teaching Point 🩺: - P. falciparum: most severe, risk of cerebral malaria, renal failure, ARDS. - P. vivax / ovale: relapsing infection due to liver hypnozoites. - P. malariae: quartan fevers, chronic nephrotic syndrome. Diagnosis: thick & thin blood films, rapid antigen tests. Management: species- and severity-specific antimalarials; prevention with prophylaxis and mosquito avoidance.