Unexpected case of chagas disease reactivation in endomyocardial biopsy for evaluation of cardiac allograft rejection

•Clinical presentation of acute Chagas disease reactivation after heart transplant•Histologic features of acute Chagas disease reactivation in endomyocardial biopsy•Epidemiologic risk-factors for Chagas disease in non-endemic countries Acute Chagas disease reactivation (CDR) after cardiac transplantation is a well-known phenomenon in endemic countries of Central and South America and Mexico, but is rare outside of those countries. In this report, we describe a case of a 49-year-old male who presented 25 weeks after heart transplant with clinical features concerning for acute rejection, including malaise, anorexia, weight loss, and fever. His immunosuppression therapy included tacrolimus, mycophenolate, and prednisone. An endomyocardial biopsy revealed lymphocytic and eosinophilic inflammation, myocyte damage, and rare foci of intracellular organisms consistent with Trypanosoma cruzi amastigotes. The patient had no known history of Chagas disease. Upon additional questioning, the patient endorsed bites from reduviid bugs during childhood in El Salvador. Follow-up serum PCR testing was positive for T. cruzi DNA. Tests for other infectious organisms and donor specific antibodies were negative. This case illustrates the striking clinical and histologic similarities between acute cellular rejection and acute CDR with cardiac involvement in heart transplant patients, and thus emphasizes the importance of pre-transplant testing for Chagas in patients with epidemiologic risk factors.