Genotyping of Mycobacterium leprae in Myanmar and supposed transmission mode

The polymorphism of TTC repeats in Mycobacterium leprae was examined using bacilli from slit skin samples of leprosy patients attending at Central Special Skin Clinic, Yangon General Hospital and nasal swabs of their contacts to elucidate the possible mode of leprosy transmission. It was found that bacilli with different TTC genotypes were distributed among same household contacts and also harbored bacilli in patients were different TTC genotype from that harbored on the nasal mucus of the healthy contacts. Genotypes of TTC repeats were found to differ between husband under treatment and his wife and also mother under treatment and her sons living in same house. This study revealed that TTC genotype of bacilli harbored by household contacts was different with the TTC genotype by index cases. These results indicate that the family members get transmission from outside the dwellings rather than from commonly supposed their MB index cases. There might have been some infectious sources to which the populace had been commonly exposed outside the dwellings.