Marcador Sorológico de Hanseníase: Implicações Epidemiológicas em Contactantes de Pacientes dos Centros de Referência Estaduais em São Luís

Abstract

Introduction: Leprosy is an infectious and contagious disease, classified as one of the neglected tropical diseases. It is transmitted through frequent and prolonged contact between susceptible individuals and infected patients. For this reason, the serological test, which detects antibodies against Mycobacterium leprae, has been used to investigate contacts of confirmed cases. As it is quick to perform and provides results in the short term, it contributes both to early diagnosis and to defining the clinical form of leprosy. Objective: To characterize leprosy cases and the profile of their contacts, evaluating the effectiveness of serological tests. Methods: This is a cross-sectional, observational study of patients diagnosed with leprosy and their household, peridomestic, and social contacts, treated at reference centers in São Luís, Maranhão (MA), Brazil. Participants underwent the ML Flow serological test. The sample consisted of two groups: leprosy patients and their contacts. Data collection took place between September 2024 and January 2025, and included interviews, signing of the Informed Consent Form (ICF), serological testing, and analysis of medical records. A pvalue of <0.05 was considered statistically significant. Results: A total of 76 patients were analyzed, with a predominance of males (80.3%) and the multibacillary form (89.5%), associated with high seropositivity (89.5%). There was a significant association between sputum smear microscopy and serology (p = 0.0062), and the ML Flow test showed 100% specificity. Among the 124 contacts, most were female (79%), and the majority were intradomiciliary (80%). Preventive examinations for leprosy were performed in 64.4% of cases. In addition, higher seropositivity was identified among consanguineous contacts, particularly children (28.3%). Conclusion: The study shows that the ML Flow test is more frequently positive in MB patients, reinforcing its usefulness as a complementary diagnostic tool. Furthermore, it concludes that the high seropositivity among contacts in the state is directly related to the intensity and frequency of exposure, high social vulnerability, and genetic predisposition.