Family Cluster Analysis of Norovirus Variants by Multiple-region Sequence Typing

描述(申请人提供)：诺如病毒(NV)现已被公认为全球所有年龄段患者腹泻的主要病原体，并被认为是急性胃肠炎的最常见原因之一。在发展中国家，据估计，新城疫感染可导致多达20万名5岁以下儿童死亡。腹泻病是这一年龄段的第二大死亡原因。最近的研究表明，新城疫在许多社区是地方性的，除了典型的暴发聚集性外，还会引起零星疾病。虽然发达国家的流行病学已经确立，但在发展中国家，由于需要进行昂贵的分子生物学来检测病毒，因此缺乏这方面的信息。此外，对不同基因类型的影响及其临床影响缺乏了解，因为 目前还没有针对该制剂的细胞培养或简单的动物模型。具体目标1.通过对NV基因组的多个区域进行基因分型，分析NV的母婴传播和家庭-儿童传播。我们将对秘鲁棚户区0-2岁儿童进行嵌套病例对照研究。将指标病例家系与两个年龄匹配的对照家系进行聚类分析。我们将确定感染相同或不同NV基因毒株的家庭成员的流行率。假设1.在指示病例的家庭中，其他家庭成员感染新城疫病毒的患病率高于对照家庭。假设2.儿童感染与母亲相同的新城疫病毒株的几率比感染其他家庭成员的几率大。假设3。大多数NV阳性的成年家庭成员将没有症状。假设4.患腹泻的儿童会有一种不在家庭其他成员中流通的基因。具体目标2。我们将评估新城疫病毒的特定变异是否是儿童新城疫相关性腹泻严重程度或排泄时间的决定因素。假设4：变异与腹泻的存在或严重程度有关。假设5.病毒载量和病毒排泄时间与特定的基因组及其变种有关。这项研究将涉及对新城疫病毒的不同区域进行测序以进行分型，目的是确定是否对疾病的严重性或病毒在社区中的传播性有不同的贡献。NV的测序有多种引物可供选择，我们将应用这些常用的引物，并开发新的引物，以提高重复性和分组能力。 公共卫生相关性：诺沃克病毒(NV)现在被认为是全球所有年龄段患者腹泻的主要原因。不幸的是，虽然发达国家已经做了很多工作，但对发展中国家的诺沃克病毒感染情况知之甚少。我们的研究将在秘鲁的一项大型研究中检查诺沃克病毒感染的许多方面，这将有助于更好地了解问题以及一些潜在的诊断和疫苗方法。

DESCRIPTION (provided by applicant): Norovirus (NV) is now recognized as the leading agent of diarrhea in patients of all ages worldwide and is known to be one of the most common causes of acute gastroenteritis. In developing countries, NV infection is estimated to cause up to 200,000 deaths in children under 5 years old. Diarrhea disease is the second leading cause of death for this age group. Recent studies have shown that NV is endemic in many communities, causing sporadic disease in addition to their classic outbreak clusters. Although the epidemiology in developed countries is well established, in developing countries this information is lacking due to the need to perform expensive molecular biology to detect the virus. In addition, knowledge of the effect of different genotypes and their clinical impact is lacking since there is no cell culture or simple animal model for this agent. Specific Aim 1. We will analyze mother-child and family-child transmission of NV by genotyping multiple region of the genome. We will conduct a nested case-control study of the children aged 0-2 years in Peruvian shanty town. Index case families will be compared with two age-matched control families by cluster analysis. We will determine the prevalence of family members infected with the same or different NV genotypic strains. Hypothesis 1. In the household of the index cases, the prevalence of other family member with NV infection is greater compared to that in the control households. Hypothesis 2. The chance that a child has the same strain of NV as the mother is greater than that with other household members. Hypothesis 3. Most of the adult family members with NV positive will be asymptomatic. Hypothesis 4. Children with diarrhea will have a genotype that is not circulating in the rest of the family. Specific Aim 2. We will evaluate whether specific variants of NV is a determinant factor of the severity of NV associated diarrhea or excretion time among children. Hypothesis 4. Variants will be associated with presence or severity of diarrhea. Hypothesis 5. Viral load and time of excretion of virus are associated with specific genogroup and its variants. This study will involve sequencing different regions of NV for typing, with the goal of determining whether there are differential contributions to the severiy of disease or transmissibility of the virus in the community. There are multiple primers available for sequencing NV, and we will apply these commonly used primers and also develop new primers to improve the reproducibility and grouping. PUBLIC HEALTH RELEVANCE: Norovirus (NV) is now recognized as the leading cause of diarrhea in patients of all ages worldwide. Unfortunately, while much work has been done in the developed world, little is known about Norovirus infections in the developing world. Our study will examine many aspects of Norovirus infection in a large study in Peru, which will lead to a better understanding of the problem as well as some potential diagnostic and vaccine approaches.