Dientamoeba fragilis: A Family Cluster of Disease Associated With Marked Peripheral Eosinophilia

: Dientamoeba fragilis has emerged as an important and underrecognized cause of gastrointestinal illness. We report a familial cluster of D. fragilis associated with marked peripheral eosinophilia and gastrointestinal symptoms. Dientamoeba fragilis infection should be considered in the setting of unexplained eosinophilia. If confirmed, screening of household members should be considered.