Cryptosporidiosis--an educational experience.

Eleven children aged 7 to 8 years from one school class developed diarrhoea and vomiting after an educational visit to a dairy farm. Three required hospital admission and intravenous fluid replacement for dehydration. Cryptosporidium oocytes were found in the faeces of these three children and from one classmate when the remainder of the class was tested between 16 and 21 days after the visit. At the farm some children tasted pelleted cow feed, silage and dried milk powder. A case-control study showed a significant correlation between diarrhoea and the tasting of silage and pelleted feed. Guidance on the safe conduct of educational visits to farms is given.