French Agency for Food, Environmental and Occupational Health & Safety, Niort Laboratory, 60 rue de Pied de Fond, 79000 Niort, France.
Vet Parasitol. 2013 Feb 18;192(1-3):268-72. doi: 10.1016/j.vetpar.2012.11.008. Epub 2012 Nov 14.
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.
一项纵向研究旨在描述法国西部一个奶牛场隐孢子虫感染的过程。两个队列分别有 25 只和 15 只动物，从出生到断奶每周采样一次。每个个体粪便样本均采用直接免疫荧光法（IFT）进行筛查，如果发现阳性，使用 PCR 分析确定隐孢子虫种类。在第一个研究中，17 只（68%[95%CI:44-91]）动物至少在第一次检查时呈阳性，在第二个研究中，IFT 检查后 14 只（93%[95%CI:80-100]）动物呈阳性。在第一个研究中，首次排泄的年龄为 17 天，排泄高峰（平均算术排泄：22700 个卵囊/克粪便）发生在 22-28 天大的幼畜。对于第二个研究，首次排泄的年龄为 10 天，排泄高峰（平均算术排泄：3.4×10^6opg）发生在 10-14 天大的动物中。只有第二个队列的动物观察到临床症状。在第一个队列的 27 个 IFT 阳性样本中，有 9 个成功进行了 18S 核糖体 RNA 基因座的 DNA 序列分析，在第二个队列的 34 个阳性分离物中，有 10 个成功进行了 DNA 序列分析。除了一个鉴定为微小隐孢子虫外，所有分离株均鉴定为小隐孢子虫。我们的结果证实，山羊幼畜是小隐孢子虫和微小隐孢子虫的宿主，并且小隐孢子虫感染可能与轻度临床症状有关。
