- Humans are inoculated with T. cruzi by infected "Reduviid Bugs" whose feces contains the organism and which deposit the protozoa on the skin while taking blood meals. The organisms enter the skin through small breaks or by auto-inoculation of the conjunctiva. T. cruzi and Reduviid Bugs are only present in the Western Hemisphere and thus Chagas Disease does display a geographic pattern of incidence.
- Acute Chagas Disease
- Acute disease manifests roughly a week after inoculation and is characterized by an erythematous and swollen skin lesion, termed a "Chagoma", along with localized lymphadenopathy at the site of inoculation. Patients display constitutional symptoms such as fever and malaise and generalized lymphadenopathy may be present. Although uncommon, some patients may develop life-threatening myocarditis leading to heart failure or Meningoencephalitis, that is meningitis together with encephalitis. For most patients the acute phase is self-limited as the immune response largely controls the infection; however, the organism is never fully eliminated and enters a dormant, subclinical existence which may last years.
- Chronic Chagas Disease
- While in most individuals the subclinical phase lasts a lifetime, for some individuals Chronic Chagas Disease manifests possibly years or decades after initial infection. Chronic Chagas Disease is caused by dilation and enlargement of a number of organs.
- Heart: Dilated cardiomyopathy which can lead to arrhythmias or mural thrombosis]
- Esophagus: Dilation of the esophagus can result in dysphagia
- Large Intestine: Megacolon can result in abdominal pain and constipation
- Historically, nifurtimox and benznidazole have been used.