**3. Microbiology and genetic**

*M. leprae* is a compulsory intracellular organism, which is a fast-staining, very slow-growing (doubling time 14 days), which can reproduce at lower temperatures than body temperature [48]. Unlike other bacteria, it is thought that the reproduction pattern is not algorithmic. While the regions where it can reproduce in human body are at 25–33**°**C, whereas no *M. leprae* involvement is observed at 35–36**°**C regions [49].

Reproduction of *M. leprae* in vitro conditions has not been fully successful until now and the reason for this is still unclear. Amako et al. reached results showing that *M. leprae* Thai-53 strain grew in vitro in different media by digital droplet PCR method [50]. Most of the studies on the *M. leprae* have been carried out on armadillos. Low body temperatures (33–35**°**) of armadillos (*Dasypus novemcinctus*), long life cycles, and adequate body sizes have made them suitable hosts in experimental areas [26].

In 2001, by dissolving the genome sequence of *M. leprae*, new information about the disease has begun to be obtained [51]. *M. leprae* has the smallest genome among the mycobacteria species. *M. leprae* bacillus has undergone severe genomic disruption and diminution with reductive evolution [52]. Reductive evolution, especially in catabolism, has removed metabolic pathways along with control pathways [53]. More than half of the genome consists of pseudogenes, inactive reading frames or regulating sequences. In addition, dominance of the bacillus genome has led to advances in topics such as molecular epidemiology, drugsusceptibility testing, and understanding of the spread of the bacterium over the world [52].
