Kala-Azar (Visceral Leishmaniasis)
Kala-azar, or Visceral Leishmaniasis (VL), is a protozoan infection caused by Leishmania donovani. It is a major target for elimination in the Indian subcontinent.
1. Epidemiology & Transmission
- Vector: Female Phlebotomus argentipes (Sandfly).
- Transmission: Bite of an infected female sandfly.
- Host: Primarily anthroponotic (human-to-human via vector) in the Indian subcontinent.
2. Clinical Features (The “Classic” Presentation)
- Fever: Often irregular or double-peak (dromedary) fever.
- Splenomegaly: Typically massive; hepatomegaly is also common.
- Pancytopenia: Anemia, leukopenia, and thrombocytopenia.
- Pigmentation: Darkening of the skin (hence “Kala-azar” or “Black Fever”).
- Weight Loss & Cachexia.
3. Diagnostic & Management Summary
| Category | Details |
|---|---|
| Gold Standard | Demonstration of amastigotes (LD bodies) in splenic aspirate. |
| Field Test | rK39 strip test (highly sensitive/specific). |
| Treatment | Single-dose Liposomal Amphotericin B (first-line). |
4. Post-Kala-Azar Dermal Leishmaniasis (PKDL)
A complication occurring months or years after treatment, presenting with macular, papular, or nodular skin lesions. These patients serve as an important reservoir for infection.
NEET PG Hint: Remember that splenic aspiration is the most sensitive diagnostic test, but it is contraindicated if the platelet count is < 40,000 or if there is a severe bleeding risk. Always prioritize rK39 as the initial diagnostic test in the field. For more high-yield infectious disease topics, visit mymedschool.org.