What is BI and MI in Leprosy?

In leprosy, BI (Bacillary Index) and MI (Morphological Index) are metrics used to assess the bacterial load and the disease's severity. The BI measures the number of Mycobacterium leprae bacteria in skin smears, while the MI evaluates the proportion of viable bacteria compared to non-viable ones in skin biopsies. These indices help in diagnosing leprosy, monitoring treatment efficacy, and determining the necessary duration of therapy. They are essential for understanding the progression and control of the disease.