Introduction

Orally transmitted acute Chagas disease has emerged in Latin America as a severe outbreak-associated presentation characterized by high parasite inoculum, systemic inflammation, and frequent early cardiac involvement. However, longitudinal evidence describing clinical phenotypes, temporal progression, and predictors of early cardiac risk remains limited. This study aimed to characterize phenotype-defined trajectories and identify determinants of severe cardiac involvement in outbreak-associated acute Chagas disease in Colombia.

Methods

This longitudinal cohort study included 104 patients diagnosed with orally transmitted acute Trypanosoma cruzi infection between 2000 and 2023. Patients were classified into predefined clinical phenotypes based on systemic severity and cardiac involvement. Temporal intervals from symptom onset to diagnosis and treatment initiation were measured. Serial electrocardiography was performed during the acute phase and at approximately 6 and 12 months. Multivariable regression models evaluated predictors of severe cardiac phenotype and intensive care admission.

Results

Three phenotypes were identified: mild systemic (28%), inflammatory non-cardiac (29%), and severe cardiac (43%). Acute myocarditis occurred in 43% of patients and electrocardiographic abnormalities in 63%. The hospitalization rate reached 82% among severe cardiac cases, and intensive care admission occurred exclusively in this group (18%). Early mortality was 2.9%, confined to fulminant myocarditis. Diagnostic delay exceeding 10 days independently predicted severe cardiac phenotype (adjusted OR 2.4; 95% CI 1.1–5.3). At 12 months, electrocardiographic abnormalities were resolved in 67% of affected individuals, while 33% had persistent alterations, predominantly among severe cardiac phenotypes.

Conclusions

Orally transmitted acute Chagas disease follows distinct phenotype-defined trajectories with markedly different early cardiac risks and recovery patterns. Severe cardiac involvement identifies a high-risk clinical course. Early diagnosis and structured cardiac follow-up are essential to reduce morbidity in outbreak settings.