Detection and characterization of group C rotaviruses in asymptomatic piglets in Ireland
Detection and characterization of group C rotaviruses in asymptomatic piglets in Ireland
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DOI：
10.1128/jcm.00809-08
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发表时间：
2008-09-01
影响因子：
9.4
通讯作者：
O'Shea, H.
中科院分区：
文献类型：
--
作者：
Collins, P. J.;Martella, V.;O'Shea, H.
C组轮状病毒是重要的人类肠道病原体，在包括猪在内的多种哺乳动物中也发现了这种病原体。在腹泻仔猪中已发现C组轮状病毒，但其生态尚不清楚。通过对2005至2007年间从爱尔兰四个猪群采集的292份4-5周龄无症状猪的粪便样本进行筛查，13份样本(4.4%)经逆转录-聚合酶链式反应(RT-PCR)检测为C组轮状病毒阳性。在19份样本中也检测到A组轮状病毒，但未与C组病毒一起检测到。对编码C组主要中和抗原外衣壳蛋白VP7的基因进行了测序。大多数菌株之间的亲缘关系非常密切(氨基酸同源性为99%)，由于它们与原型猪品系考登(92.6%的氨基酸同源性)在遗传上有亲缘关系，因此被鉴定为基因群G1。相反，两个毒株(1GA/05/Cork/Ire和281/07/Dublin/Ire)与猪G6毒株(43/06-22-like)具有最高的同源性(89.2%~94.0%aa)，因此被鉴定为G6基因组。出乎意料的是，这样的G6毒株1GA/05/CORK/IRE在所有其他G6组C组轮状病毒中都缺乏VP7可变区VR8中的4-AA插入。这项研究提供的证据表明，猪C组轮状病毒在无症状的仔猪中可能并不少见。此外，它还提供了证据表明，与人类病毒不同，猪C组轮状病毒表现出广泛的遗传异质性，这可能对预防工具的开发构成挑战。
Group C rotaviruses are important human enteric pathogens that have also been detected in a variety of mammalian species, including pigs. Group C rotaviruses have been identified in piglets with diarrhea, but their ecology remains to be elucidated. By screening of 292 fecal samples collected from 4- to 5-week-old asymptomatic pigs from four herds in Ireland between 2005 and 2007, 13 (4.4%) samples tested positive by reverse transcription-PCR for group C rotavirus. Group A rotaviruses were also detected in 19 samples but not in conjunction with group C viruses. The gene encoding the major group C neutralization antigen, the outer capsid protein VP7, was sequenced. The majority of the strains were very closely related to each other (> 99% amino acid [aa] identity) and were characterized as genogroup G1 since they were genetically related to the prototype porcine strain Cowden (92.6% aa identity). Conversely, two strains (1GA/05/Cork/Ire and 281/07/Dublin/Ire) were characterized as genogroup G6 since they displayed the highest identity (89.2 to 94.0% aa) to porcine G6 strains (43/06-22-like). Unexpectedly, one such G6 strain, 1GA/05/Cork/Ire, lacked the 4- aa insertion in the VP7 variable region VR8 found in all the other G6 group C rotaviruses. This study provides evidence that porcine group C rotavirus may be detected not infrequently in asymptomatic piglets. In addition, it provides evidence that, unlike the human viruses, porcine group C rotaviruses display broad genetic heterogeneity, which may pose a challenge for the development of prophylactic tools.