The bacteriological index (BI) in leprosy measures which of the following?
- A Logarithmic count of bacilli per unit area on slit-skin smear ✓
- B Viability of Mycobacterium leprae based on solid-staining morphology
- C Percentage of morphologically intact bacilli
- D Granuloma formation index on histopathology
Correct answer: A. Logarithmic count of bacilli per unit area on slit-skin smear
Explanation
BI (bacteriological index) uses Ridley's logarithmic scale (0 to 6+) to quantify bacillary density in slit-skin smears, expressing the number of AFB per oil-immersion field. The morphological index (MI) measures the percentage of uniformly stained (solid) bacilli, reflecting viability. BI decreases slowly with MDT (over years) whereas MI falls rapidly within weeks, making MI a better early monitor of treatment response.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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