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

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.