Study of a novel picornavirus genus associated with Acute Flaccid Paralysis

描述（由申请人提供）：仅在2008年，有脊髓灰质炎病毒活跃监测计划的国家报告了85,400例急性弛缓性麻痹（AFP）病例，其中不到1,731例（2.03%）被发现与脊髓灰质炎病毒感染有关。使用宏基因组方法，我们在患有非脊髓灰质炎AFP的儿童中发现了一组高度分化的小核糖核酸病毒。6种新病毒的全基因组测序和系统发育分析表明，它们与目前已知的所有小核糖核酸病毒有足够的差异，可以在小核糖核酸病毒科中形成一个新属。为了开始检测这些被命名为人类cosav病毒（HCoSV）的新病毒是否是与非脊髓灰质炎AFP相关的重要病原体，我们使用特异性PCR引物检测了160例非脊髓灰质炎AFP病例的粪便样本。在107例AFP患者的粪便样本中检测到HCoSV RNA。多发性AFP患儿粪便样本中HCoSV变异的高流行率和高病毒载量使我们假设HCoSV是一种与儿童AFP相关的人类病原体。HCoSV变异的初步系统发育分析表明，在这个新的小核糖核酸病毒属中存在四种不同的病毒种。子宫颈病毒属种间的遗传分化程度与肠病毒属种间相似。现在需要关于HCoSV遗传多样性和流行病学的进一步信息，以阐明其在AFP中的致病作用，如果得到证实，则用于制定预防其传播和疾病的战略。AIM 1将确定来自大量AFP病例和人口统计学匹配的健康对照样本中不同HCoSV基因型的患病率，以测试是否与AFP有显著关联，然后对最不同的HCoSV变体进行全基因组遗传表征。AIM 2将使用细胞培养产生的病毒粒子或杆状病毒/昆虫细胞表达衍生的病毒衣壳开发HCoSV的血清学检测。AIM 3将确定AFP病例、健康对照者和一般人群中HCoSV血清反应的流行率。因此，我们最近在发展中国家对一种新的人类小核糖核酸病毒属进行了鉴定和高频率检测，这一探索性研究将为可能采取的步骤提供基础，以减轻婴儿麻痹性疾病造成的仍然很高的健康负担。我们的长期目标是确定HCoSV的致病潜力并预防新的感染。

DESCRIPTION (provided by applicant): In 2008 alone, 85,400 cases of acute flaccid paralysis (AFP) were reported from the countries with active poliovirus surveillance programs, of which less than 1,731 (2.03%) were found to be associated with poliovirus infection. Using a metagenomic approach we have discovered a group of highly divergent picornaviruses in children suffering from non-polio AFP. The complete genomes of six new viruses were sequenced and phylogenetic analysis indicated them to be sufficiently divergent from all currently known picornaviruses to form a new genus in the Picornaviridae family. In order to begin testing whether these new viruses, named Human Cosavirus (HCoSV), were a significant pathogen associated with non-polio AFP we tested stool samples from 160 non-polio AFP cases using specific PCR primers. HCoSV RNA was detected in stool samples of 107 AFP cases. High prevalence and high viral load of HCoSV variants in stool samples of multiple AFP children leads us to hypothesize that HCoSV is a human pathogen associated with AFP in children. Initial phylogenetic analysis of HCoSV variants showed the existence of four different viral species within this new Picornaviridae genus. The level of genetic divergence between species of genus Cosavirus was similar to that between species of genus Enterovirus. Further information regarding HCoSV genetic diversity and epidemiology is now required to clarify its pathogenic role in AFP and, if confirmed, for developing strategies to prevent its transmission and disease. AIM 1 will determine the prevalence of different HCoSV genotypes in samples from a larger number of AFP cases plus demographically matched healthy controls to test whether there is a significant association with AFP, followed by full genome genetic characterization of the most divergent HCoSV variants. AIM 2 will be the development of a serological assay for HCoSV using virions produced by cell culture or viral capsids derived from baculovirus/insect cell expression. AIM 3 will determine the prevalence of seroreactivity to HCoSV in AFP cases, in healthy controls and in the general population. This exploratory study of a new human picornavirus genus that we have recently characterized and detected at high frequency in developing countries will therefore provide the foundation for possible steps to relieve the still high health burden imposed by infantile paralytic diseases. Our long-term goal is to define the pathogenic potential of HCoSV and to prevent new infections.