Cryptosporidiosis associated with traveling and giardiasis.

The aim of this study was to reveal sources where cryptosporidiosis may be acquired. We studied 4545 patients, from whom 5730 stool samples were obtained for the diagnosis of parasitic infections during 13 mo, and found that 119 of these patients (2.62%) excreted oocysts of Cryptosporidium. About two-thirds of the patients reported no animal contacts. There were no cases among children under the age of 5 yr, which is evidence against endemicity, and the prevalence was highest (6.22%) in young adults aged 15-29 yr. The sex distribution was unremarkable: of the 119 patients, 56 were men and 63 were women. Most patients reported a recent trip abroad, which had taken place 12 times more frequently during the previous month than earlier. Cryptosporidiosis was five times more frequent in patients who had recently visited Leningrad than in others, and seven times more frequent in patients with Giardia lamblia than in others. Sporadic cryptosporidiosis occurs mainly in travelers, and seems to be acquired from similar sources as giardiasis.