DETECTION OF MYCOBACTERIUM-LEPRAE NASAL CARRIERS IN POPULATIONS FOR WHICH LEPROSY IS ENDEMIC

In order to better understand the role of Mycobacterium leprae nasal c arriage in the maintenance of infection reservoirs and transmission of leprosy, we applied a polymerase chain reaction (PCR) that detected a 531-bp fragment of the pra gene of M. leprae on nasal swab specimens collected through a total population survey from individuals living in an area in which leprosy is endemic. Among the total tested populatio n of 1,228 people, 7.8% were found to be PCR positive. PCR positivity was shown to be randomly distributed among the population for which le prosy is endemic. No association was observed between PCR positivity, age, or sex. The observed distribution of PCR positivity among househo lds of different sizes confirmed the expected values, with the excepti on of two households, each with three people with PCR-positive nasal s wab specimens. Although nasal carriage does not necessarily imply infe ction or excretion of bacilli, the finding of nasal carriage supports the theory of a disseminated occurrence of M. leprae in populations fo r which leprosy is endemic.