Prevalence of Cryptosporidium among patients with acute enteric infection.

Twelve hundred faecal samples from patients suspected of acute enteric infection were examined for Cryptosporidium oocysts by means of a modified Ziehl-Neelsen technique. Smears prepared from the formol-ether sediment of 400 faecal samples were compared with those made directly from faeces. The numbers of positive patients were identical, but the diagnosis was easier to make with smears prepared from sediment. Cryptosporidia were found in 21 samples and after correction for duplicates the net result was 16 cases (2%) of cryptosporidiosis diagnosed among 800 patients. Except in one case Cryptosporidium was the only pathogen found. Fourteen patients had diarrhoea while excreting the parasite. All the patients recovered spontaneously within 3 weeks. Nine of them had recently travelled abroad; for three others, infected calves may possibly have been the source of infection. Carriers were not found among 120 persons without gastro-intestinal symptoms.