[Hansen's disease in the laboratory].

A physical doctor with a PhD in Pathology, Euzenir Nunes Sarno studies the immunology factors of Hansen's disease, one of the oldest chronic infections and that is an exclusively human disease. Staff member of an ambulatory that has become a reference on the disease in Brazil with 220 to 250 new patients per year, Euzenir emphasizes that the fact one cannot cultivate Mycobacterium leprae brings about some everlasting questions in relation to the transmission of and the sensitivity to the disease. There are also many epidemiology questions that remain unanswered. Estimates show that, among those who have contact with multi-bacilli patients, 90% are infected but only about 8% get sick. The high infection rate of those who live with multi-bacilli patients but never fall sick shows that just a small number of individuals are sensitive to Mycobacterium leprae. This is one of the questions immunology has not been able to answer. Why do some people resist to it and some don't? The figures are even lower when compared to those who are in contact with patients that are paucibacillus-infected, i.e. a manifestation of the disease with few bacilli. Hansen's disease is known as a skin malady. But, according to the specialist, its first damage is to the nerve, when the area becomes insensitive. Besides damaging the sensitive skin nerves, the disease can lead to motor disability and irreversible deformities, which sometimes lead to the amputation of limbs and protruded parts of the body. Mycobacterium leprae was one of the first pathogenic bacteria whose genome sequence has been entirely mapped. Only now we have the capacity to have more precise assessments. The disease is not inherited, and only in 1986 health services in Brazil began to take the responsibility for both the disease and its patients. During the twenty-year military dictatorship the country underwent, the health system was dismantled. In 1991, the one-year treatment with three drugs - Dapsone, Rifanpicine and Clofazimine- was introduced in our country. Just 30% of the cases get to negative results after the treatment. according to the interviewee, whereas tuberculosis is a highly virulent multi-bacilli disease, leprosy bacillus is not virulent, is a 'lazy' germ at the end of its evolutional process. One third of its genome does not work.