Final answer:
The presentation of dysphagia with parasites observed in blood smears suggests Chagas disease caused by T. cruzi. Diagnostic confirmation involves direct microscopic observation, IFA, EIAs, PCR, culturing, or xenodiagnosis. Confirming the presence of T. cruzi is essential for appropriate treatment.
Step-by-step explanation:
The patient's symptoms of dysphagia to solids and liquids, along with the observation of motile parasites in thick/thin blood smears stained with Giemsa, suggest an infection with the parasite T. cruzi, which causes Chagas disease. Dysphagia and associated achalasia can occur in the chronic phase of Chagas disease due to the parasitic infection of gastrointestinal tissues leading to nerve damage.
Diagnostic steps for confirming Chagas disease include direct microscopic observation of trypanosomes in blood smears, Immunofluorescence Assay (IFA), Enzyme Immunoassays (EIAs), Polymerase Chain Reaction (PCR), and culturing in artificial media. In endemic regions, xenodiagnosis is also an option, where uninfected triatomine bugs feed on the patient and their feces are examined for T. cruzi. These diagnostic methods will help confirm the presence of the T. cruzi parasite and allow for appropriate treatment decisions.