Unexpected activity of β-cyclodextrin against experimental infection by Cryptosporidium parvum

An unexpected activity of beta -cyclodextrin, an excipient used in pharmaceutical technology, was observed against Cryptosporidium parvum. The viability and infectivity of purified oocysts, exposed for 24 hr to beta -cyclodextrin (2.5% suspension), were evaluated by inclusion/exclusion of 2 fluorogenic vital dyes and a suckling murine model, respectively. Results of the viability assay showed a high proportion of nonviable oocysts (81.5%). The intensity of experimental infection, determined 7 days postinoculation by examination of intestinal homogenates, was significantly lower (P < 0.05) than in the control litters. The preventive and curative efficacies of <beta>-cyclodextrin suspension were also evaluated in experimentally infected neonatal mice. Infection was prevented when the suspension was administered 2 hr before inoculated oocysts and on days 1 and 2 postinoculation.