Cryptosporidium bovis n. sp (Apicomplexa: Cryptosporidiidae) in cattle (Bos taurus)
Cryptosporidium bovis n. sp (Apicomplexa: Cryptosporidiidae) in cattle (Bos taurus)
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DOI：
10.1645/ge-3435
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发表时间：
2005-06-01
影响因子：
1.3
通讯作者：
Xiao, LH
中科院分区：
文献类型：
--
作者：
Fayer, R;Santín, M;Xiao, LH
标题隐孢子虫属一新种。C.牛本文介绍C.牛乳孢子虫（Coptosporidium）基因型为牛B（GenBank AY 120911），在形态上与C.小的它们完全孢子化排出，含有4个子孢子，但缺乏孢子囊。卵囊大小为4.76-5.35 μ m（平均值= 4.89 μ m）× 4.17-4.76 μ m（平均值= 4.63 μ m），长宽比为1.06（n = 50）。卵囊对新生BALB/c小鼠无感染性，但对2头先前感染C.小的卵囊没有感染性的2个实验暴露的羔羊小于1周龄，未检测到42羔羊2-3月龄，但在2周龄羔羊中检测到。在早期的一项研究中，7个州14个奶牛场的840头小牛中有79头被发现感染了新物种。大多数小牛为2-7月龄，无腹泻体征。在马里兰州的一个牛肉农场的162头9至11个月大的小牛中，有10头发现了这种新物种。PCR扩增18 S rDNA、HSP-70和actin基因片段，并对纯化的PCR产物进行测序。对3个非连锁位点的多位点分析表明，该新种与C. parvum，也表现出缺乏重组，提供了物种地位的进一步证据。基于这些生物学和分子生物学数据，我们认为这种高度流行的隐孢子虫主要感染断奶后的小牛是一个新的物种，并提出名称隐孢子虫牛。sp.对于这种寄生虫。
A new species of Cryptosporidium. C. bovis. is described. Oocysts of C. bovis, previously identified as Coptosporidium genotype Bovine B (GenBank AY 120911), are morphologically indistinguishable from those of C. parvum. They are excreted fully sporulated and contain 4 sporozoites, but lack sporocysts. Oocysts measure 4.76-5.35 mu m (mean = 4.89 mu m) X 4.17-4.76 mu m (mean = 4.63 mu m), with a length-to-width ratio of 1.06 (n = 50). Oocysts were not infectious for neonatal BALB/c mice, but were infectious for 2 calves that were previously infected with C. parvum. Oocysts were not infectious for 2 experimentally exposed lambs less than 1 wk of age and were not detected in 42 lambs 2-3 mo of age, but were detected in a 2-wk-old lamb. In an earlier study, 79 of 840 calves on 14 dairy farms in 7 states were found infected with the new species. Most calves were 2-7 mo of age and none exhibited signs of diarrhea. This new species has been found in 10 of 162 calves aged 9 to 11 mo on a beef farm in Maryland. Fragments of the 18S rDNA, HSP-70, and actin genes were amplified by PCR, and purified PCR products were sequenced. Multilocus analysis of the 3 unlinked loci demonstrated the new species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further evidence of species status. Based on these biological and molecular data, we consider this highly prevalent Cryptosporidium that infects primarily postweaned calves to be a new species and propose the name Cryptosporidium bovis n. sp. for this parasite.