The potential role of environmental M. leprae in the transmission of leprosy remains unknown. We investigated role of environment as a possible source of viable M. leprae responsible for transmission of leprosy. The samples were collected from 10 multi-case leprosy families comprising, slit skin smear (SSS) from 9 multibacillary (MB), 16 paucibacillary cases (PB), 22 household contacts, and 38 environmental soil samples. The quantum of viable M. leprae was estimated by qRT-PCR using 16S rRNA gene from soil and SSS. Genotypes of M. leprae were determined by gene sequencing. We could observe presence of viable M. leprae in 11 (44%) leprosy cases (M. leprae 16S rRNA gene copies range from 1.78 × 10² to 8.782 × 10⁹) and 4 (18%) household contacts (M. leprae 16S rRNA gene copies range from 2.54 × 10³ and 7.47 × 10⁴). Remarkably, presence of viable M. leprae was also noted in 10 (53%) soil samples where in M. leprae 16S rRNA gene copies ranged from 4.36 × 10² to 7.68 × 10². M leprae subtype 1D was noted in most of the leprosy cases their household contacts and in the surrounding soil samples indicating source of infection in household contacts could be from environment or patients. M. leprae 16S rRNA copies were approximately similar in both PB cases and soil samples along with presence of SNP type 1 subtype 1D in both samples indicating source of M. leprae from patients to contacts was either from patients or environment or both.

环境麻风分枝杆菌在麻风传播中的潜在作用仍然未知。我们调查了环境的作用，认为它可能是负责麻风传播的活麻风杆菌的可能来源。样本是从10个多病例麻风病家庭中采集的，包括来自9个多细菌（MB）的狭缝皮肤涂片（SSS），16个多杆菌性细菌（PB），22个家庭接触者和38个环境土壤样​​品。使用来自土壤和SSS的16S rRNA基因通过qRT-PCR估算了活麻风杆菌的数量。通过基因测序确定麻风分枝杆菌的基因型。我们可以观察到11例（44％）麻风病患者存在麻风分枝杆菌（麻风分枝杆菌16S rRNA基因拷贝范围为1.78×10 ²至8.782×10 ⁹）和4个（18％）家庭接触者（麻风分枝杆菌16S rRNA基因拷贝范围为2.54×10 ³和7.47×10 ⁴）。值得注意的是，在10个（53％）土壤样品中还发现了活麻风杆菌的存在，其中麻风杆菌16S rRNA基因的拷贝范围为4.36×10 ²到7.68×10 ²。中号麻风杆菌亚型1D在大多数的麻风病例的家庭接触和指示感染的家庭接触的来源可以是来自环境或患者周围的土壤样品中指出。麻风分枝杆菌16S rRNA在PB病例和土壤样品中，拷贝数都近似相似，并且在两个样品中都存在SNP 1型亚型1D，这表明从患者到接触者的麻风分枝杆菌的来源是来自患者或来自环境或两者都有。