Prevalence of Giardia duodenalis genotypes in pre-weaned dairy calves
Prevalence of Giardia duodenalis genotypes in pre-weaned dairy calves
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DOI：
10.1016/j.vetpar.2004.07.010
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发表时间：
2004-10-05
影响因子：
2.6
通讯作者：
Fayer, R
中科院分区：
文献类型：
--
作者：
Trout, JM;Santín, M;Fayer, R
为了确定断奶前仔牛中贾第鞭毛虫基因的流行率，从佛蒙特州、纽约州、宾夕法尼亚州、马里兰州、弗吉尼亚州、北卡罗来纳州和佛罗里达州的两个农场的每个农场至少18头1-7周龄的奶牛中收集粪便样本。清除粪便残渣，用CsCl2密度梯度离心法浓缩，进行染色，免疫荧光显微镜检查，并进行聚合酶链式反应和基因序列分析。聚合酶链式反应的流行率从宾夕法尼亚州农场的9%到佛蒙特州农场的93%不等，14个农场407头小牛的平均流行率为40%。对TPI、β-giardin和16S rRNA基因的序列分析表明，85%的阳性样本是E组合，15%的阳性样本是A组合，尽管这些基因的百分比在不同的农场有很大的差异。一些农场没有贾第虫的集合体。因此，虽然大多数牛犊感染了一种对人类未知的基因，但14个农场中的7个牛犊确实携带着贾第鞭毛虫。应将牛犊视为环境中人类感染性包囊的潜在来源。爱思唯尔出版公司(Elsevier B.V.)
To determine the prevalence of Giardia genotypes in pre-weaned dairy calves, fecal samples were collected from a minimum of 18, 1-7-week-old dairy calves per farm on two farms each in the states of Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Samples cleaned of fecal debris and concentrated using CsCl density gradient centrifugation were stained and examined by immunofluorescence microscopy and also subjected to PCR and gene sequence analysis. Prevalence by PCR ranged from 9% on a farm in Pennsylvania to 93% on a farm in Vermont, with an average prevalence for 407 calves on 14 farms of 40%. Gene sequence analysis of the TPI, beta-giardin and 16S rRNA genes revealed 85% of the positive samples to be Assemblage E, while 15% were Assemblage A, although the percentages of these genotypes varied greatly from farm to farm. Some farms had no Assemblage A Giardia. Thus, while a majority of the calves were infected with a genotype that is not known to be infectious for humans, calves on 7 of 14 farms did harbor Assemblage A Giardia. Calves should be considered as a potential source of human infectious cysts in the environment. Published by Elsevier B.V.