# Trachoma prevalence surveys in 15 indigenous and non-indigenous evaluation units in Brazil, 2018–2023

## TL;DR

This study surveyed trachoma prevalence in 15 Brazilian regions, finding it likely eliminated as a public health issue, but highlighting poor sanitation in indigenous areas.

## Contribution

First-time reporting of trachoma data from six evaluation units and insights into socioenvironmental disparities in sanitation.

## Key findings

- Trachomatous inflammation prevalence in children was below the 5% elimination threshold in all EUs.
- TT prevalence was below 0.2% in 14 EUs, with a 58% likelihood of elimination in one mesoregion.
- Indigenous EUs showed over 10% of households without sanitation and high open defecation rates.

## Abstract

To provide the groundwork for a future declaration of elimination of trachoma as a public health problem in Brazil, we conducted house-to-house surveys following WHO methodological guidance.

An observational cross-sectional study was conducted in 10 non-indigenous and five indigenous evaluation units (EUs) from 2018 to 2023; data on six EUs are reported here for the first time. Two-stage cluster sampling was used: 30 clusters per EU, and 30 households per cluster. We estimated the prevalence of trachomatous inflammation—follicular (TF) in 1–9-y-olds and trachomatous trichiasis (TT) unknown to the health system in those aged ≥15 y. Data on sanitary conditions were collected in household interviews.

In all EUs, TF prevalence was below the elimination threshold (5%). TT prevalence was lower than the 0.2% threshold in 14 EUs. In ‘Noroeste Cearense’ mesoregion, TT prevalence was 0.22% (95% CI 0.06 to 0.44%), but statistical analysis showed a 58% likelihood of TT elimination in this EU. In three indigenous EUs, >10% of households had no sanitary facilities and high percentages of open defecation.

It is highly likely that trachoma has been eliminated as a public health problem in all the EUs surveyed. The findings on sanitary conditions mandate public policies to overcome socioenvironmental inequalities.