Croatian Veterinary Institute, Virology Department, Savska cesta 143, 10000 Zagreb, Croatia.
Infect Genet Evol. 2013 Mar;14:258-64. doi: 10.1016/j.meegid.2012.12.027. Epub 2013 Jan 8.
Astroviruses are emerging viral agents, primarily enteropathogenic in mammals, but recently have been acknowledged to have extra-intestinal implications in humans and mink. Porcine astrovirus is thought to be widely distributed and highly prevalent among pigs, nevertheless its clinical significance remains doubtful as it can be detected in diarrheic as well as in healthy pigs. Recent reports imply the immense genetic variability among porcine astrovirus strains with five distinct lineages being characterized so far. Herein, we report porcine astrovirus circulation in the blood of healthy pigs in different age categories bred on two large industrial holdings in Croatia, with viral RNA seroprevalence of 3.89%. These are the first extra-intestinal findings of astrovirus in pigs, indicating a more complex pathogenesis than previously thought. Partial polymerase sequences of serum-derived strains provisionally clustered into porcine astrovirus lineages 2 and 4, sharing high genetic identity with previously described porcine astrovirus strains. The results were supported by detecting porcine astrovirus strains in composite fecal samples, regardless of pig category or holding tested. Phylogenetic analysis of derived strains suggested the presence of porcine astrovirus lineages previously detected in pig sera with an additional highly genetically divergent lineage 5, reported for the first time in Europe. Moreover, the existence of possible sub lineages should not be excluded. The results obtained in the present study, contribute to knowledge of porcine astrovirus pathogenesis; even though it's possible clinical significance remains unclear. High fecal prevalence accompanied with vast genetic diversity on a relatively confined area, underscores the importance of pigs as porcine astrovirus reservoirs with eventual recombination events as a possible outcome.
星状病毒是新兴的病毒病原体，主要在哺乳动物中引起肠道疾病，但最近已被确认在人类和水貂中有肠道外影响。猪星状病毒被认为广泛分布且在猪中高度流行，但由于在腹泻和健康猪中均可检测到该病毒，因此其临床意义仍存在疑问。最近的报告表明，猪星状病毒株具有巨大的遗传变异性，迄今为止已经鉴定出了五个不同的谱系。在此，我们报告了在克罗地亚两个大型工业养殖场不同年龄段的健康猪血液中猪星状病毒的循环情况，其病毒 RNA 血清流行率为 3.89%。这是首次在猪中发现肠外星状病毒，表明其发病机制比以前认为的更为复杂。从血清中分离的部分聚合酶序列暂定聚类为猪星状病毒谱系 2 和 4，与先前描述的猪星状病毒株具有高度遗传同源性。无论测试的猪类别或养殖场如何，在复合粪便样本中检测到猪星状病毒株都支持了这些结果。衍生菌株的系统发育分析表明，存在以前在猪血清中检测到的猪星状病毒谱系，以及以前在欧洲首次报道的高度遗传分化的谱系 5。此外，不应排除可能存在亚谱系的可能性。本研究的结果有助于了解猪星状病毒的发病机制；尽管其可能的临床意义仍不清楚。在相对有限的区域内，高粪便流行率伴随着巨大的遗传多样性，突显了猪作为猪星状病毒储主的重要性，最终可能会发生重组事件。
