# Visceral leishmaniasis risk clusters on Brazil’s borders: 2013 to 2022

## TL;DR

This study shows that visceral leishmaniasis in Brazil's border areas has uneven patterns over time and space, with some regions needing urgent attention for control.

## Contribution

The study identifies specific high-risk clusters and temporal trends of visceral leishmaniasis in Brazilian border regions from 2013 to 2022.

## Key findings

- The highest incidence rates were observed among children, adolescents, and males in the Central Arc region.
- The Central Arc region showed a decreasing trend from 2013-2020 but an increasing trend from 2020-2022.
- Persistent high-risk clusters were found in the North Arc and Central Arc, with a notable cluster near the Foz do Iguaçu triple border.

## Abstract

Visceral leishmaniasis remains a significant public health burden in the Americas, particularly in Brazil and its border regions. This study aims to analyze the temporal trends and spatial clusters of visceral leishmaniasis in Brazilian border municipalities in 2013-2022.

An ecological study was conducted, using secondary population-based data. Joinpoint regression was used to assess temporal trends and estimate the annual percentage change (APC). Kulldorff’s scan statistics identified spatial clusters and relative risks (RR).

During the period, 677 visceral leishmaniasis cases were reported in the border municipalities (average annual incidence rate: 0.58). The highest cumulative IR was observed among children and adolescents (10.05, 95% CI: 9.02-11.16), males (7.17, 95% CI: 6.50-7.88), and in the Central Arc 13.55, 95% CI: 12.25-14.95). Central Arc showed a decreasing trend from 2013-2020 (APC: -11.65%, 95% CI: -27.28-5.91) and an increasing from 2020-2022 (APC: 55.76%, 95% CI: 6.70-101.96), with RR rising 21.059 (2016-2019) to 34.310 (2020-2022). Persistent high-risk clusters were identified in the North Arc (RR: 100.529-156.040) and Central Arc (RR: 20.716-34.310), alongside a high-risk cluster in the South Arc near the Foz do Iguaçu triple border (RR: 3.466).

This study revealed that visceral leishmaniasis in the Brazilian border region presents heterogeneous spatial and temporal patterns. Achieving effective disease control by 2030 will require strengthened health interventions and coordinated multilateral collaboration among neighboring countries, focusing on high-risk areas.