Landscape modeling as a surveillance strategy for Trypanosoma cruzi vectors in Brazil.

BACKGROUND

The transmission of Trypanosoma cruzi in nature is closely linked to the ecology of its vectors, the triatomine insects. Although the geographic distribution of these species is relatively well-known, understanding the characteristics that define their ecological niche and how human interventions alter these conditions remains limited. Rapid and intense environmental changes, driven by activities such as agricultural expansion, raise important questions about how vector ecology is being transformed and the new implications for Chagas disease transmission risk.

METHODS

This study aimed to develop Ecological Niche Models (ENMs) to map the environmental suitability for 14 triatomine species and T. cruzi in Brazil and to evaluate the impact of landscape modifications. Environmental variables were selected based on Spearman correlation, and models were generated using Maxnet, Random Forest, and Support Vector Machines. To ensure prediction robustness, only models with a True Skill Statistic (TSS) ≥ 0.7 were considered. Based on these predictions, a risk classification was developed that integrates vector diversity and parasite presence to identify areas with higher transmission risk.

RESULTS

The results revealed a significant ecological transition of the vectors, which are adapting from natural ecosystems to agroecosystems, particularly pastures and soybean cultivation, bringing the transmission cycle closer to humans. Risk analyses indicated that the Midwestern, Northern, Northeastern, and Southeastern regions are the most vulnerable, with actual risk strongly associated with modified landscapes.

CONCLUSIONS

The integrated use of geotechnologies proved essential for identifying and understanding the spatial distribution of vectors and the parasite, as well as for quantifying the impact of human activity. These findings provide important insights for improving Chagas disease surveillance and control strategies, considering the environmental complexity and ecological heterogeneity involved in its transmission.Graphical abstract is mandatory for publication in this journal. Please provide the graphical abstract.The graphical abstract has been included as a attachment.