Anti-PGL-I serology as a strategy for Hansen’s Disease control in an endemic area in Brazil

Background Hansen’s Disease (HD), caused by Mycobacterium leprae, remains a global health concern, particularly in Brazil. Mossoró, a city in Rio Grande do Norte State, presents high HD incidence and has been a focus for disease control efforts. Objective This study aimed to assess the utility of a qualitative anti-PGL-I antibody rapid test for screening multibacillary (MB) HD cases among males in high-risk neighbourhoods of Mossoró. Methods The study comprised serological testing using the ML Flow rapid test on males aged 18 and above living in seven hyperendemic neighbourhoods independently of known HD contact. Seropositive individuals underwent medical assessment and received home visits for evaluation of their contacts. Results Among 623 individuals tested, 87 (14%) were seropositive for anti-PGL-I IgM antibodies and four among 79 who attended a medical assessment (5.1%) were confirmed as new HD cases. The mapping and spatial density analysis of seropositivity among individuals without HD reflected differences in the geographic distribution of HD cases in the municipality. Among 210 contacts examined, four additional HD cases were identified. Limitations The study’s focus on male population in specific neighbourhoods did not represent the whole urban area. Conclusion Although the leprosy new case detection rate obtained with this strategy was only 0.6% of all tested individuals, the study suggests that mapping anti-PGL-I seropositivity in the healthy population can aid in identifying HD high-risk areas. Future research with broader population samples is recommended to validate these findings and enhance HD control strategies in endemic regions.