Objective analyze serological profile and spatial distribution of Mycobacterium leprae infection and disease. Methods cross-sectional study with cases of leprosy (n=42), household contacts (n=81) and school contacts (n=358). Interviews, dermato-neurological examination, serological and georeferencing made. Results all seropositive cases lived in rural areas, more than two people per household, 50.0% had alteration of foot strength. 75.0% were elderly and married participants. Among seropositive schoolchildren, 75.0% female, 69.4% lived with more than four people 80.6% slept in the bedroom with someone. It was possible to observe hyper endemic areas of cases in the studied municipality and spatial-temporal relation among them (p=0.010). In addition, concentration of cases and schoolchildren in sectors of lower family income per capita was found. Conclusion the serological analysis revealed that the cohabitation condition was related to the Mycobacterium leprae infection, and the spatial analysis showed a hidden endemic scenario.

Descritores Objetivo analisar o perfil sorológico e a distribuição espacial da infecção e do adoecimento pelo Mycobacterium leprae. Métodos estudo transversal, conduzido com casos de hanseníase (n=42), contatos intradomiciliares (n=81) e escolares (n=358). Realizados entrevista, exame dermatoneurológico, sorológico e georreferenciamento dos endereços. Resultados dos casos soropositivos, todos residiam em zona rural, com mais de duas pessoas no domicílio, 50,0% apresentavam alguma alteração de força nos pés. Dos contatos soropositivos, 75,0% eram idosos e casados. Dentre os escolares, 75,0% eram do sexo feminino, 69,4% residiam com mais de quatro pessoas e 80,6% dormiam no quarto com alguém. Foi possível observar áreas hiperendêmicas de casos no munícipio estudado e relação espaço-temporal entre eles (p=0,010). Além disso, concentração de casos e escolares em setores de menor renda familiar per capita. Conclusão a análise sorológica revelou que a condição de convivência se relacionou com a infecção pelo Mycobacterium leprae, e a espacial demonstrou cenário de endemia oculta.

OBJECTIVES Show that hidden endemic leprosy exists in a municipality of inner São Paulo state (Brazil) with active surveillance actions based on clinical and immunological evaluations. METHODS The study sample was composed by people randomly selected by a dermatologist during medical care in the public emergency department and by active surveillance carried out during two days at a mobile clinic. All subjects received a dermato-neurological examination and blood sampling to determine anti-PGL-I antibody titers by enzyme-linked immunosorbent assay (ELISA). RESULTS From July to December 2015, 24 new cases of leprosy were diagnosed; all were classified as multibacillary (MB) leprosy, one with severe Lucio's phenomenon. Seventeen (75%) were found with grade-1 or 2 disability at the moment of diagnosis. Anti-PGL-I titer was positive in 31/133 (23.3%) individuals, only 6/24 (25%) were positive in newly diagnosed leprosy cases. CONCLUSIONS During the last ten years before this study, the average new case detection rate (NCDR) in this town was 2.62/100,000 population. After our work, the NCDR was raised to 42.8/100,000. These results indicate a very high number of hidden leprosy cases in this supposedly low endemic area of Brazil.

Leprosy in children is correlated with community-level factors, including the recent presence of disease and active foci of transmission in the community. We performed clinical and serological examinations of 1,592 randomly selected school children (SC) in a cross-sectional study of eight hyperendemic municipalities in the Brazilian Amazon Region. Sixty-three (4%) SC, with a mean age of 13.3 years (standard deviation = 2.6), were diagnosed with leprosy and 777 (48.8%) were seropositive for anti-phenolic glycolipid-I (PGL-I). Additionally, we evaluated 256 house-hold contacts (HHCs) of the students diagnosed with leprosy; 24 (9.4%) HHC were also diagnosed with leprosy and 107 (41.8%) were seropositive. The seroprevalence of anti-PGL-I was significantly higher amongst girls, students from urban areas and students from public schools (p < 0.0001). Forty-five (71.4%) new cases detected amongst SC were classified as paucibacillary and 59 (93.6%) patients did not demonstrate any degree of physical disability at diagnosis. The results of this study suggest that there is a high rate of undiagnosed leprosy and subclinical infection amongst children in the Amazon Region. The advantages of school surveys in hyperendemic areas include identifying leprosy patients at an early stage when they show no physical disabilities, preventing the spread of the infection in the community and breaking the chain of transmission.