Effect of nitazoxanide on cryptosporidiosis in experimentally infected neonatal dairy calves.

Abstract

Cryptosporidium is a zoonotic protozoan that is most often diagnosed in association with diarrhea in 1- to 3-wk-old dairy calves. There are neither consistently effective nor approved antimicrobial drugs for treatment in animals. The objective of this study was to test nitazoxanide (NTZ) as a treatment for cryptosporidiosis in experimentally infected dairy calves. A randomized, controlled, and blinded trial was performed using Holstein bull calves obtained from a large commercial dairy. All births were attended by study personnel and calves were fed 4 L of heat-treated colostrum within 1 h of birth. Calves were randomly assigned to treatment or placebo group and maintained for a 32-feeding (16 d) study period. Twenty-three calves were enrolled with 3 lost to follow up. Thirteen calves were assigned to the treatment group and 7 calves to the placebo group. All calves were inoculated with 1 x 10(6) viable Cryptosporidium parvum oocysts at feeding 3. Treatment was a commercially available NTZ product and the placebo was the carrier of the same product. Nitazoxanide was administered at 1.5 g twice per day for 5 d. Nitazoxanide or placebo treatment began after feeding 10 and when the fecal score was greater than 1 out of 3. Outcome measurements included twice-daily fecal and health scores and a once-daily oocyst count by an immunofluorescent antibody assay. Data were analyzed by nonparametric and time-to-event methods. Measures of passive transfer of antibodies, initial body weight, and onset of oocyst shedding were not different between treatment and control calves. Eighty-five percent of the NTZ-treated calves stopped shedding oocysts by the end of the observation period whereas only 15% of the placebo group stopped shedding. The median number of feedings with a fecal score equal to 3 was 2 in the NTZ group while it was 6 in the placebo group. Calves receiving NTZ were 0.13 times as likely to have severe and sustained diarrhea than control calves (95% confidence interval, 0.02-0.98). Treating calves with NTZ reduced the duration of oocyst shedding and improved fecal consistency.

• Authors: T L Ollivett, D V Nydam, D D Bowman, J A Zambriski, M L Bellosa, T C Linden, T J Divers
• Journal: Journal of dairy science (J Dairy Sci) Vol. 92 Issue 4 Pg. 1643-8 (Apr 2009) ISSN: 1525-3198 [Electronic] United States
• PMID: 19307646 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Antiparasitic Agents
• Nitro Compounds
• Thiazoles
• nitazoxanide

Topics

• Animals
• Animals, Newborn
• Antiparasitic Agents (therapeutic use)
• Cattle
• Cattle Diseases (drug therapy, parasitology)
• Cryptosporidiosis (drug therapy, veterinary)
• Dairying
• Feces (parasitology)
• Kaplan-Meier Estimate
• Male
• Nitro Compounds
• Oocysts (physiology)
• Thiazoles (therapeutic use)