# Insights into leprosy epidemiology from an isolated population located in the Brazilian Amazon

## TL;DR

This study explores leprosy patterns in an isolated Brazilian Amazon village, revealing higher prevalence and earlier diagnosis among locals compared to newcomers.

## Contribution

The study provides novel insights into leprosy epidemiology using data from a unique, hyper-endemic, isolated population.

## Key findings

- Cumulative leprosy prevalence was 22.9% among villagers born in the village versus 5.9% among those not born there.
- The median age at diagnosis was 15 years for villagers born in the village versus 28 years for others.
- No gender difference in leprosy case distribution was observed in the study population.

## Abstract

Leprosy, a chronic infectious disease caused mainly by Mycobacterium leprae (M. leprae), is still an important public health problem in countries such as Brazil and India. Here, we estimate key epidemiological parameters in the Prata Village, a unique, hyper-endemic, former leprosy colony isolated in the Brazilian Amazon. This is a population-based study in which the entire Prata Village population has been enrolled. Clinical, socioeconomic, and demographic data were obtained and validated by cross-checking using three independent information sources. Validated data was used for descriptive epidemiological analysis. From a total of 2,005 inhabitants by the time of the enrollment, 1,084 (56.2%) were born in the Village and, therefore, likely under lifelong exposure to leprosy cases. We observed differences between the sub-populations born and not born in the village in the cumulative prevalence of leprosy (5.9% vs. 22.9%, respectively) and the median age at diagnosis (15 years vs. 28 years, respectively). In contrast, there was no difference in the distribution of cases between males and females. Although extrapolating our findings to more open populations must be done carefully, we believe we used a unique population as a model to provide additional insights into the epidemiology of leprosy.

The online version contains supplementary material available at 10.1038/s41598-025-90399-0.