There is an association between anti-PGL 1 positivity and development of leprosy, but we cannot state that anti-PGL 1 result reflects recent infection by M. leprae. The relationship is more complex and involves host immunity: patient with tuberculoid form (TT) of leprosy are not positive to PGL-1, and for sure, they are infected with M. leprae. Because of this, the test cannot be used to measure infection rate in communities, as suggested by some papers [9,23]. Here, SDHD is linked to infection.