A previously healthy 2-year-old boy was referred to the Department of Gastroenterology at Shanghai Children's Hospital after experiencing irregular stools for 10 months and bloody diarrhea for 2 days. Despite repeated treatment with antidiarrheals and probiotics at the local medical facilities, the child's condition gradually worsened and he was failing to thrive. He lived in a rural area and he did not eat raw food or have allotriophagia but occasionally played in the dirt. On presentation, the child was 11.9 kg (-1SD) in weight, 90 cm in height (-1SD) and 46 cm in head circumference, with no change in the past 10 months. The child's whole abdomen was flat and soft, with no tenderness and rebounding pain, and bowel sound was 4-5 times/min. Blood examination showed white blood cells 13.54 x 109/L (normal range: 8.0-12.0 x 109/L), eosinophils 1,000 x 106/L (normal range: 50-450 x 106/L), accounting for 7.9%, hemoglobin 103 g/L (normal range: 110-160 g/L), serum albumin 42.5 g/L (normal range: 38-54 g/L), globulin 25 g/L (normal range: 13-21 g/L), erythrocyte sedimentation rate 42 mm/h (normal range: 0-20 mm/h), and immunoglobulin E increased by 538 IU/mL (normal range: 0-60 IU/mL). No parasite egg was found in the patient's fecal test for four times before admission, by using direct smear microscopy. However, fecal occult blood test was positive. After admission, a concentration procedure was performed to identify parasite eggs in the patient's fecal sample through a liquid-based parasite detection kit. Parasite eggs were not found. The age of the patient, duration of the disease and poor response to previous treatment led us to conclude that the etiology was unclear, requiring further examination.
Abdominal and pelvic enhanced computed tomography of the patient showed no abnormalities. Esophagogastroduodenoscopy revealed chronic superficial gastritis and duodenitis. The gastric mucosal biopsy suggested chronic moderate non-atrophic gastritis, with 3-5 eosinophils per high power feild (HPF). The mucosal biopsy of duodenal bulb showed slight changes in the villi and crypt structure, and infiltration of lamina propria lymphocytes and plasma cells, with 5-8 eosinophils/HPF. In the colonoscopy, there were many white and transparent parasites about 2-3 cm length in the whole colon, some of which were curly, and peristalsis was visible. The white-striped parasites adsorbed on the colon wall could not be washed away easily (Fig. 1a). In the right colon, a large number of parasites had gathered, and the colon mucosa was slightly pale, accompanied by patchy hyperemia, edema, and erosion, which was consistent with parasitic colitis (Fig. 1b). Part of the parasite bodies were removed with a net and sent for pathological examination. The male mature trichurid and a large number of fusiform eggs in the female trichurid body could be seen. The thick eggshells and a plug at both ends were consistent with trichurid egg (Fig. 1c). The diagnosis of irritable bowel syndrome, intestinal tuberculosis, clostridium difficile infection, henoch-schonlein purpura and inflammatory bowel disease could be excluded, finally resulting in a diagnosis of trichuriasis infection. Oral albendazole tablets (400 mg/day, once daily) were administrated for seven consecutive days, and the patient's diarrhea improved significantly until he gradually had a regular stool. Written informed consent was obtained from the patient's parents for publication of their child's personal or clinical details.