Symptoms and transmission of intestinal

Cvyptosporidium spp are a cause of diarrhoea in toddlers. Symptoms and routes of transmission were investigated in a prospective casecontrol study in the city and surroundings of Basel, Switzerland. Twenty one (4.6%) out of 455 children with diarrhoea who attended paediatric and general practices from June to September 1988 were positive for cryptosporidium. The mothers of each case, of two controls with diarrhoea of another origin, and of two healthy controls were interviewed with a standardised questionnaire. In comparison with controls with diarrhoea of another origin, respiratory symptoms were significantly more frequent in children with cryptosporidiosis: eight of 19 (42%) compared with five of 38 (13%). In comparison with healthy controls, preceding contact with a person suffering from diarrhoea was associated with the greatest relative risk for cryptosporidiosis, followed by travel in a Mediterranean country. Transient cryptosporidial infection of the respiratory tract may be common in immunocompetent children. In the area investigated person to person transmission may account for most cases. Swiss Tropical Institute, Basel, Switzerland, Department of Public Health and Epidemiology M Egger D Mausezahl P Odermatt M Tanner Department of Diagnostics H-P Marti Correspondence to: Dr M Tanner, Department of Public Health and Epidemiology, Swiss Tropical Institute, Socinstrasse 57, PO Box, 4002 Basel, Switzerland. Accepted 22 November 1989 Cryptospotidium spp, a coccidian parasite first described in 1907,' has only recently been recognised as a relatively frequent cause of diarrhoea in children. In Switzerland 5-5% of children with diarrhoea identified by a laboratory based survey were found to be positive for oocysts of Cryptosponidium spp.2 In immunocompetent children the disease is usually self limiting, but it may be severe in immunodeficient patients.2 3 Cryptosporidiosis has been considered as an 'emerging zoonosis' with reservoirs in cattle and domestic animals, and in the faecally contaminated environment.4 Other ways of transmission have been reported, including person to person transmission,5 and transmission by contaminated food and waterfor example, when travelling.6 Outbreaks in daycare centres and families have been