Makindo Medical Notes

The risk of infection is highest from dusk to dawn, when sand flies are most active. Amphotericin B is now the treatment of choice due to rising resistance to pentavalent antimonials.

📖 About

• Three major forms: Cutaneous (CL), Mucocutaneous (MCL), and Visceral (VL).
• Spread by infected sand flies:
  • Lutzomyia species in the New World.
  • Phlebotomus species in the Old World.
• Protozoan parasites of the Leishmania family.
• Endemic in Central/South America, Africa, India, Middle East, Asia, Southern Europe, and the Mediterranean.

🧬 Mechanism of Infection

• Inoculated promastigotes are phagocytosed by macrophages.
• They transform into amastigotes, multiply by binary fission, and evade nitric oxide killing.
• Rupture of infected macrophages → spread to other cells in the reticuloendothelial system.

🦟 Transmission

• Vector: infected sand flies living in mud huts and rural dwellings.
• Peak biting activity: evening, twilight, and night.
• Sand fly bites are silent and painless; lesions may go unnoticed until ulcers appear weeks to months later.
• Lesions may cause scarring; mucosal disease can lead to nasal destruction.
• Regional lymphadenopathy or lymphangitis may accompany skin lesions.

🩺 Clinical Manifestations

• Cutaneous Leishmaniasis (CL)
  • Geography: Mexico, Central/South America, Middle East, Asia, N. Africa, Southern Europe.
  • Parasites multiply in dermal macrophages near inoculation site → nodules/ulcers on arms, legs, face, ears.
  • Classic ulcer: painless, chronic, may be called the “Baghdad boil”.
  • May be mistaken for leprosy.
  • Diagnosis: slit skin smear from raised ulcer edge or nodule centre (shows amastigotes).
• Mucocutaneous Leishmaniasis (MCL)
  • Mainly in South America.
  • Causes destructive lesions of nose, nasopharynx, palate, uvula, larynx, and upper airways.
• Visceral Leishmaniasis (VL, “Kala-azar”)
  • Most severe form; frequently fatal if untreated.
  • Caused by L. donovani, L. infantum, L. chagasi.
  • Incubation up to 2 years (usually 8 months).
  • Dissemination via macrophages → reticuloendothelial system.
  • Symptoms: prolonged fever, weight loss, massive splenomegaly > hepatomegaly, pancytopenia.

🔍 Investigations

• FBC: anaemia, leucopenia, thrombocytopenia; low albumin, raised globulins.
• Diagnosis:
  • Amastigotes (Leishman-Donovan bodies) on bone marrow aspirate.
  • Tissue scraping: amastigotes within macrophages.
  • Splenic aspirate (if safe: INR normal, platelets >40) – very sensitive.
• Consider co-infections: TB, dysentery, pneumonia; advanced disease predisposes to cancrum oris.
• Note: treated patients may later develop Post-kala-azar dermal leishmaniasis (PKDL), remaining reservoirs of infection.

💊 Management

• Amphotericin B is the treatment of choice (liposomal form preferred where available).
• Miltefosine or paromomycin may be used as alternatives in some regions.
• Cutaneous lesions: may heal spontaneously but can require antimonials, amphotericin, or cryotherapy depending on severity.
• Supportive care: treat malnutrition, secondary infections, and anaemia.

🛡️ CDC Advice (Prevention)

• Stay in screened/air-conditioned rooms; avoid outdoor activities from dusk to dawn.
• Wear protective clothing (long sleeves, trousers, socks, tucked-in shirt).
• Apply insect repellents with DEET (30–35% for adults; ≤10% for children aged 2–6; avoid in <2 years).
• Spray clothes with permethrin-containing insecticides; reapply after washing.
• Spray rooms with insecticides; sand flies are highly susceptible.
• Use fine-mesh bed nets (≥18 holes per inch), ideally treated with permethrin.