Chronic Cyclospora infection in a heart transplant patient with intestinal malabsorption: a case report

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.