Clinical report of Blastocystis hominis infection in children.

During a 9-month hospital-based survey, the intestinal parasite Blastocystis hominis was detected in high numbers (five or more organisms per oil immersion field) in faecal specimens from 39 (2%) of 1960 children under 13 years old. Abdominal pain or discomfort with or without diarrhoea was present in 32 children categorized as acute (14), subacute (7) or chronic (11) cases with respective mean ages of 6.4, 7.3 and 8.7 years. They included three with other enteropathogens (Giardia lamblia, Cryptosporidium sp. or Hymenolepis nana). The remaining seven children had no gastrointestinal symptoms. The 14 acute cases (symptoms duration 1-11 days) were characterized by cramp-like abdominal pain, watery diarrhoea and vomiting. The seven subacute (3-4 weeks) and 11 chronic (3-12 months) cases presented with abdominal discomfort and/or loose non-watery stools. Four complained of flatus and eosinophilia was noted in six. All symptoms resolved with eradication of B. hominis or reduction to low numbers after metronidazole chemotherapy (28 cases) or with no treatment (four cases). This study would appear to support the role of the parasite as an enteropathogen in some children. A case control study is clearly needed to clarify the status of B. hominis as a pathogen.