Shedding of oocysts by immunocompetent individuals with cryptosporidiosis.

Studies were made on 33 immunocompetent patients with cryptosporidiosis (31 of them children) to determine how long oocyst shedding continued after the cessation of diarrhoea. The majority (20/33) ceased to shed oocysts in the week following the cessation of diarrhoea. However 5 patients (15%) continued to shed oocysts for 2 weeks or more, and 1 patient was still shedding oocysts when lost to follow-up 3 weeks after the diarrhoea ceased. There was considerable variation among patients, and some eliminated oocysts more efficiently and quickly than others. The sucrose flotation technique was more useful than direct smear for detecting the low numbers present at the end of the shedding period. Limited information suggested that a carrier state or relapse is probably rare.