Treatment with β-cyclodextrin of natural Cryptosporidium parvum infections in lambs under field conditions

Following the unexpected activity of the excipient beta -cyclodextrin against experimental infection by Cryptosporidium parvum in suckling mice, its efficacy in the prevention and treatment of natural infections in lambs was evaluated Under field conditions. Fifty-three crossbred neonatal lambs were randomly selected for the study. Treatment consisted of oral administration of an aqueous suspension of beta -cyclodextrin at a dose of 500 mg/kg of body weight. To test prophylactic efficacy, the suspension was administered at 1, 2 and 3 days of age. To evaluate therapeutic efficacy, the suspension was administered on each of the 3 days following onset of diarrhoea. Infection was monitored by daily examination of faecal samples, from birth to 30 days. The criteria studied in evaluating efficacy were: oocyst shedding, the presence of diarrhoea, and weight gain at 15 and 30 days. In the group that received prophylactic treatment A with beta -cyclodextrin, there were no mortalities and, compared with control lambs, there was a decrease in the number of animals infected, a longer prepatent period and notable reduction in the patent period and the duration of diarrhoea. Therapeutic treatment also reduced the patent period and the severity of diarrhoea. beta -cyclodextrin was well tolerated by all of the treated animals. (C) 2001 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.