Abdominal Discomfort With Weakness and Weight Loss in a 21-Year-Old Man

A 21-year-old Fulani man presents to a local hospital in Kano, Nigeria with a history of recurrent, mild abdominal discomfort. The patient complains of weakness, weight loss, occasional diarrhea, and anal itching. He has no history of fever, headache, cough, subcutaneous nodules, or altered skin pigmentation. He has visited various clinics, at which he received multiple unknown medications for his condition. The patient resorted to attempting traditional remedies when he felt that he had not improved with prescription medications. Of note, the patient has observed occasional instances of a "threadlike worm" in his stool.

He has no history of hospital admissions, blood transfusion, or surgery. He lives with his extended family in proximity to livestock. The patient is single. He denies drinking alcohol, smoking, and using any prescribed drugs. He has no known drug allergies.

On physical examination, the patient is a tall, lean, young man who appears apprehensive and mildly pale. He has a pulse rate of 75 bpm with a regular rhythm, a blood pressure of 120/80 mm Hg, a respiratory rate of 14 breaths/min without respiratory distress, and a normal temperature. He is 5 ft 7 in (1.7 m) tall and weighs 104 lb (47 kg). The patient has no palpable lymphadenopathy and no scleral icterus or edema is observed. The patient has a normal thyroid examination and no rashes or subcutaneous nodules are noted.

Normal breath sounds are found on the pulmonary examination. The cardiac examination demonstrates normal S1 and S2 heart sounds with no murmur, gallops, or rubs. There is no evidence of jugular venous distension. The abdomen is soft and without organomegaly. Rectal examination reveals no masses, with dark stool noted. He is cooperative and has normal mentation. The patient demonstrates no focal findings on neurologic examination, including no cranial nerve palsies, muscle weakness, or loss of sensation; additionally, normal reflexes are elicited.

The laboratory investigations include a complete blood cell count with a hematocrit of 26% and an eosinophil count of 0.5 x 10⁹/L. Other hematologic parameters examined are within the normal range. Abdominal ultrasonography is normal. On stool microscopy, small, white, rice-like bits are noted.

So, can you tell me the diagnosis?