[Leprosy epidemiology in a cohort of household contacts in Rio de Janeiro (1987-1991)]. / Epidemiologia da hanseníase em coorte de contatos intradomiciliares no Rio de Janeiro (1987-1991).

This study aimed to identify factors influencing the development of leprosy (Hansen's disease) in household contacts. A dynamic cohort was analyzed from 1987 to 1991 at the Hansen's Disease Department of the Oswaldo Cruz Foundation in Rio de Janeiro. The incidence rate was 0.01694 person-years of follow-up. Nevertheless, for subjects at the end of the first year of follow-up the incidence rate was 0.06385 (end of second year, 0.03299; end of third year, 0.02370; end of fourth year, 0.018622; and end of observation period, 0.01694). A stepwise multivariate logistic regression model was proposed to study the risk of developing leprosy, including co-prevalent cases, totaling 758 contacts. In the final model, the risk was associated with a negative Mitsuda skin test (OR = 3.093; CI 95% = 1.735-5.514), prior BCG vaccination (OR = 0.3802; CI 95% = 0.2151-0.66719), and multibacillary primary clinical form (OR = 2.547; CI 95% = 1.249-5.192). The results showed that both multibacillary leprosy and specific immune status are significant indicators for developing the disease in a cohort of household contacts.

Two multidrug fixed-dosage treatment regimens with multibacillary leprosy patients.

This study compares the clinical, bacilloscopic, and histopathological evolution of 140 patients classified as having multibacillary leprosy with no previous specific treatment who were submitted to two multidrug treatment regimens with a fixed dose. Regimen I-Group 1: 70 cases received 600 mg rifampicin (RMP) + 100 mg dapsone (DDS) daily for three consecutive months followed by 100 mg DDS daily, self-administered doses for 21 months. Regimen II-Group II: 70 cases received 600 mg RMP + 300 mg clofazimine (CLO) once a month under supervision plus self-administered doses of 50 mg CLO + 100 mg DDS daily for 24 months. The bacilloscopic, histopathological and neuromotor evaluation parameters showed no statistically meaningful differences (P > 0.05) between the two groups except for reaction frequency (P < 0.05) in that group II patients presented the least number of reactional episodes during the treatment and in the dermatological examination at discharge. Follow-up after treatment was carried out for a consecutive four year period. During routine clinical examination one case submitted to regimen I developed nodular skin lesion over the right arm. Skin biopsy was done for histopathological examination and mouse foot-pad experiment by Shepard technique. The drug susceptibility test with DDS and RPM showed that M. leprae strain isolated was susceptible to both the drugs.

Mycobacterium leprae-induced interferon-gamma production by household contacts of leprosy patients: association with the development of active disease.

Identification of individuals at risk for developing leprosy and their early diagnosis are central to effective disease control. Lack of immunologic response to Mycobacterium leprae among persons exposed to the infectious agent may be predictive of susceptibility. M. leprae-induced interferon-gamma (IFN-gamma) production by peripheral blood mononuclear cells was used as a measure of immune responsiveness. Household contacts of multibacillary patients likely to be at risk of developing active disease were identified, and a preliminary analysis after 2 years of follow-up is presented. A persistent in vitro negative response to M. leprae was present in 34.6% of the contacts, and a decrease in IFN-gamma production was noted in 52.5%. Five contacts (6.41%) developed leprosy during follow-up and, as predicted, belonged to the group of individuals who were negative or showed reduced levels of IFN-gamma in response to the antigen.