*5.3.3 Interminate phase*

The interminate phase is almost asymptomatic, but progresses to a chronic, symptomatic phase, including the gradual development of irreversible life-threatening and disabling comorbidities, especially to those who are immunosuppressed. Physical examination is normal, and resting electrocardiogram is normal. Only special inspection method can find abnormalities. This is the beginning of the chronic phase. This type can persist for 20 to 30 years, or even life.

## *5.3.4 Chronic stage*

During the chronic phase, the parasite hides mainly in the muscles of the heart and digestive tract. Ten to thirty years later, up to 30% of patients develop cardiac disorders and up to 10% develop gastrointestinal (typically enlarged esophagus or colon), neurological, or mixed lesions. In later years, infections in these patients can lead to myocardial and neurological damage, followed by arrhythmias or progressive heart failure and sudden death. The disease usually begins years or decades after the onset of parasitemia. (1) Cardiomyopathy in endemic areas: trypanosomiasis cardiomyopathy is the main cause of heart disease and sudden death. Patients often develop congestive heart failure with an enlarged heart. Two-thirds of patients have cardiac conduction disorders, often right bundle branch block, polygenic premature contractions, and myocardial necrosis. The disease course can be short and sudden death, or death from long-term heart failure. In addition, emboli from the apex or atrium can cause sudden death due to cerebral or pulmonary embolism. (2) Dilation of multiple organs: in Brazil, Chile, and some parts of Argentina, there are multiple organ expansions, mainly the esophagus and colon. Difficulty swallowing is often caused by esophageal expansion, constipation caused by colon expansion, and volvulus may also occur, such as acute abdomen. As for the giant stomach, giant duodenum, giant bronchus, giant ureter, etc. have been reported but rare.
