Impacto da busca ativa especializada no diagnóstico da hanseníase: avaliação longitudinal e comparativa de aspectos clínicos e laboratoriais em áreas endêmicas no Pará e no Maranhão

Abstract

Leprosy is a disease that represents a significant public health problem in various parts of the world, including Brazil. To improve epidemiological data, active case finding activities and longitudinal research represent a transformative approach to disease control. In this context, the present study aimed to evaluate and compare the clinical and laboratory aspects of patients with leprosy, their contacts, and schoolchildren over a one-year period in endemic areas in Pará and Maranhão. To achieve this, a longitudinal study was conducted, characterized by active case finding activities in Imperatriz-MA, São Luís-MA, and Marituba-PA, where registered leprosy cases in the Notifiable Diseases Information System (SINAN), their contacts, and school-aged children were evaluated. Participants underwent neurodermatological evaluation and blood collection for the titration of IgM anti-PGL-I antibodies, as well as intradermal scraping of the earlobes and elbows for bacilloscopy and qPCR. After one year, in 2023, participants from the municipalities of Imperatriz and São Luís were re-evaluated, and new participants were included. Among 522 individuals included in this study, 135/522 (25.9%) were clinically and/or laboratorially re-evaluated in 2023, and 387/522 (74.1%) were evaluated exclusively in 2022 or 2023. In 2022, new cases were identified among 66/221 (29.9%) contacts and 23/195 (11.8%) schoolchildren. Additionally, 9/34 (26.5%) relapses and 2/34 (5.9%) patients with therapeutic insufficiency or failure were diagnosed among index cases. In 2023, new cases were observed among 70/126 (55.5%) contacts and 10/29 (34.4%) schoolchildren. Furthermore, 7/12 (58.3%) relapses and 1/12 (8.3%) patients with therapeutic insufficiency or failure were diagnosed among index cases. In the neurodermatological evaluation, among schoolchildren and contacts who were re-evaluated, individuals with an altered superficial fibular nerve were found to be 4.3 times more likely to be in the disease case group (p < 0.05; 95% CI = 1.58- 12.74; OR = 4.32). The bacilloscopy test identified the etiological agent in 7/222 evaluated individuals (3.1%), with 4/7 (57.1%) being among individuals with a prior diagnosis of leprosy. Regarding the serological analysis of re-evaluated individuals, seropositivity was observed in 26/106 (24.5%) individuals in 2022, and 7/106 (6.6%) in 2023, a statistically significant decrease (p < 0.05). A high positivity rate for the qPCR technique was observed, including 9/10 (90%) relapses, 55/88 (62.8%) new cases, and 43/151 (48.3%) contacts. These data highlight a concerning scenario characterized by a high number of hidden leprosy cases in the analyzed regions, and a significant increase in diagnosis rates after one year of follow-up in the communities, underscoring the importance of longitudinal research and the implementation of different diagnostic and monitoring techniques for a better understanding of leprosy and its outcomes in endemic areas.