A case-control study was conducted to determine the presence of Mycobacterium leprae
DNA in nasal secretions
of leprosy cases and nonleprosy individuals in Fortaleza, Brazil. It included 185 cases identified by physicians at the
Dona Libânia National Reference Centre for Sanitary Dermatology (CDERM). A control group (Co) (n = 136) was
identified among individuals from CDERM not diagnosed as leprosy cases. To augment the spatial analysis of M. leprae
specific repetitive element (RLEP) positive prevalence, an external group (EG) (n = 121), a convenience sample of
healthy students, were included. Polymerase chain reaction for the RLEP sequence was conducted for all participants.
Prevalence of RLEP positivity for cases and Co were 69.2% and 66.9%, respectively, significantly higher than for EG
(28.1%), and reported elsewhere. Male sex, belonging to a lower socioeconomic status (D/E), history of a previous contact
with a case and being older, were associated with being a leprosy case. Our geographical analysis demonstrated
that the bacillus is widespread among the healthy population, with clusters of RLEP positive multibacillary cases concentrated
in distinct areas of the city. Our results suggest that in endemic areas, as in Fortaleza, surveillance for both
nonhousehold leprosy contacts and members of the general population living in cluster areas should be implemented.