Presença de M. leprae na mucosa bucal: identificação de uma potencial via de infecção e transmissão da hanseníase

Abstract

Leprosy is an important health problem in Brazil, with a high detection rate despite the application of the multidrug therapy. The nasal mucosa is considered the preferential site of entry and exit of the Mycobacterium leprae, although some lesions have been found in the buccal mucosa. However, the buccal mucosa involvement in bacilli transmission has never been investigated. We have shown the presence of the M. leprae DNA in buccal swabs of leprosy patients (334) and household contacts (1288) through conventional polymerase chain reaction (PCR), and results were correlated with clinical and other laboratorial evaluations. The overall positivity for patients was 18.26%, divided into 12.03% and 21.23% for paucibacillary and multibacillary forms, respectively. Among contacts, the positivity reached 6.83%, which were considered either as healthy carriers or sub-clinically infected, when the ELISA test presented a positive anti-PGL-1 result. This study showed important evidences that the buccal mucosa may be a secondary site of M. leprae transmission and infection. Furthermore, contacts with positive PCR may be actively involved in the transmission. Our findings have great epidemiological relevance, especially for the leprosy control programs and for the dentistry clinics, and must be considered in the new strategies of control and prevention.