Abstract
BACKGROUND: Cyclosporiasis is a rare cause of chronic diarrhea and malabsorption in immunosuppressed patients. CASE SUMMARY: We report an unusual case of chronic Cyclospora infection in a heart transplant patient with a five-month history of watery diarrhea and weight loss. Initial stool testing failed to discover a causative pathogen. Duodenal biopsy showed histologic findings of intraepithelial lymphocytosis and partial villous blunting, raising the possibility of celiac disease. A repeat duodenal biopsy five months later revealed intracellular parasites with gametocyte, meront, and schizont forms, and the diagnosis of Cyclospora infection was confirmed by BIOFIRE Gastrointestinal (GI) Pathogen Panel. CONCLUSION: Morphologic diagnosis of enteric parasite infections is challenging and requires a high level of clinical suspicion in immunosuppressed patients. In addition to significant exposures and travel history, chronic immunosuppression should prompt extensive microbial testing, including stool ova and parasite, acid-fast testing, and/or multiplex PCR for GI pathogens in post-transplant patients with unexplained diarrhea.