[A survey of giardiasis in an asylum for mentally retarded children]

A 10-year-old mentally retarded girl from an asylum in northern Taiwan was diagnosed to have giardiasis with malabsorption syndrome at the Department of Pediatrics, National Taiwan University Hospital in 1983. A survey for giardiasis in 239 children living in the same asylum was therefore performed. Stool specimens were collected from all children, and giardia was examined simultaneously by formalin-ether concentration method and polyvinyl alcohol preservation followed by Trichrome stain. Forty one cases (17.2%) of giardiasis were detected by the former method while 48 cases (20.1%) by the latter method. Abnormally low stool trypsin activity was found in 38 of the 42 cases (90.5%) tested and the activity returned to normal in 50% of patients after successful treatment. Endoscopic examination and intestinal biopsy of upper gastrointestinal tract were performed in 12 cases. Among them, 4 were found to have nodular lymphoid hyperplasia, lymphoid hyperplasia in 7, and increased mononuclear cell infiltration in lamina propria in 7. Forty patients were treated with metronidazole 250 mg three times a day for 5 days. Follow-up stool examinations revealed that 12 children (30%) still passed giardia in their stools 4 months after treatment. Reinfection and inadequate sensitivity of the initial screening test may be used to account for such a high rate of treatment failure.