Asymptomatic Trypanosoma cruzi Infection Identified During Blood Donation Screening.

Chagas disease, also known as American trypanosomiasis, is caused by the protozoan Trypanosoma cruzi. The global burden of Chagas disease, particularly in non-endemic regions, is increasing due to migration. In the chronic phase, which can last until treatment is administered, the majority of infected individuals remain asymptomatic. This can lead to challenges in diagnosis and increase the risk of patients developing severe, late complications. Diagnosis in chronic cases depends on serologic testing since parasitemia is low. CDC guidelines recommend confirmation with two distinct serologic assays, as screening tests alone are not sufficient for diagnosis.  We describe the case of a middle-aged woman from Panama who was found to have asymptomatic T. cruzi infection incidentally during routine blood donor screening. Two serologic assays per CDC guidelines confirmed the initial positive enzyme immunoassay. Limited access to first-line therapy (benznidazole) necessitated treatment with nifurtimox. The patient's serologic titers declined following therapy, signifying a response to treatment. This case highlights the importance of clinician familiarity with CDC diagnostic protocols, the limitations of blood donor screening as a diagnostic tool, and the treatment access barriers for Chagas disease in the United States. It also highlights the absence of standardized criteria for assessing treatment success in chronic infection. Addressing these concerns would ensure timely diagnosis, initiation of therapy, and appropriate monitoring to prevent the development of disease complications.