Molecular characterization of Cryptosporidium spp. in pre-weaned kids in a dairy goat farm in western France.

A longitudinal study was undertaken to characterize the course of Cryptosporidium infection in a dairy goat farm located in western France. Two cohorts of twenty-five and fifteen animals, respectively, were sampled once a week from birth to weaning. Each individual fecal sample was screened using direct immunofluorescence (IFT) and if found positive, the Cryptosporidium species was identified using PCR analysis. Seventeen (68% [95% CI: 44-91]) animals were positive at least once during the first study and 14 (93% [95% CI: 80-100]) during the second, after IFT examination. In the first study, the age at first excretion was 17 days and the peak of excretion (mean arithmetic excretion: 22,700 oocysts per gram (opg) of feces) was recorded when kids were between 22 and 28 days old. For the second study, the age at first excretion was 10 days and the peak of excretion (mean arithmetic excretion: 3.4 × 10(6)opg) was recorded in animals aged between 10 and 14 days. Clinical signs were observed only in animals of the second cohort. DNA sequence analysis at the 18S ribosomal RNA locus was successful for 9 of the 27 IFT-positive samples in the first cohort and for 10 of the 34 positive isolates in the second cohort. All isolates were identified as Cryptosporidium xiaoi except one which was identified as Cryptosporidium parvum. Our results confirm that goat kids are hosts for C. parvum and C. xiaoi and that infection by C. xiaoi may be associated with mild clinical signs.