To ask the Secretary of State for Health what information his Department holds on the incidence of morbidity in children resulting from the ingestion of cryptosporidium oocysts.

This information is not collected centrally. A study carried out by the Public Health Laboratory Service in 1985–87 covering over 60,000 patients, identified cryptosporidium infection in 2 per cent. of cases. Cryptosporidium infection was found in 4.9 per cent. of one to four-year-olds.