UCP1 and infection: This study describes the largest field application of the anti-PGL-I UCP-LFA to date (n = 33,128 tests), using humoral immunity in the population (anti-M. leprae-specific seroprevalence), to assess the impact of PEP implementation including repeated door-to-door screening on population infection levels, rather than merely evaluating the number of newly detected cases many years after PEP.