Trypanosoma cruzi infections cause Chagas disease. Like the previous infectious agent (Babesia) , this small parasite lives in the red blood cells of wild or domestic mammals. Kissing bugs, also known as triatomine bugs, become infected when feeding upon these mammals. When these bugs subsequently take a meal from a human, general at night in a bed, it defecates, leaving T. cruzi in the feces. The T. cruzi enters the human host through the bite wound or by being exposed to mucous membranes such as the mouth. Here they enter red cells, replicate and burst these red ells, and get sucked up by other Kissing bugs further infecting other people. This is a common disease in South America and much rarer in the United States. Acutely, Chagas disease often goes undetected (often a localized swelling at the site of entry). After 10-20 years of chronic infection, internal organs, particularly the heart, can be severely affected and manifest as heart failure. Acute cases are treated with anti-parasitic drugs; effective therapy for chronic cases is not available. Chagas disease usually causes impairment in the electrical activity of the heart and heart failure. Development of an immune response to the disease that cross reacts with the heart itself is thought to be involved in the development of myocarditis in some patients.