Hookworm infection in a healthy adult that manifested as severe eosinphilia and diarrhea

A 54-year-old male was admitted because of having suffered from progressive watery diarrhea for 12 days. He had no history of diabetes mellitus, hypertension, heart disease, organ transplantation, or malignancy. After admission, he still complained of diarrhea despite medical treatment. The laboratory examination showed leukocytosis with eosinophilia and a stool examination by the concentration method was negative four times. When a sigmoidoscopy was performed as a part of an explorative survey, a single protruding mass consisting if a moving adult hookworm was found. The fifth stool examination by the concentration method identified hookworm ova. The patient was treated with oral mebendazole 100 mg twice a day for 3 days. The diarrhea and eosinophilia subsided after this treatment.