In vitro and in vivo efficacy of lasalocid for treatment of experimental cryptosporidiosis.

In vitro viability of purified Cryptosporidium parvum oocysts, exposed for 30, 60, 90 and 120min to 0.27mg/ml lasalocid suspension was evaluated by inclusion or exclusion of two fluorogenic vital dyes and an excystation technique. Continuously, preventive and curative efficacies at different doses (9, 6.75, 5.625 and 4.5mg/kg body weight) and regimens of lasalocid against cryptosporidial infection were evaluated on an experimental neonatal mice model. In vitro assays demonstrated a decrease in the oocyst viability related to an increase in exposure time for exposure to the lasalocid suspension. The infection was eradicated when the suspension was administered with a dose of > or = 6.75mg/kg body weight. No apparent toxic effects were observed.