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

描述（由申请方提供）：诺如病毒（NV）现在被认为是全球所有年龄段患者腹泻的主要病原体，并且已知是急性胃肠炎的最常见原因之一。在发展中国家，NV感染估计导致多达20万5岁以下儿童死亡。腹泻病是这一年龄组的第二大死因。最近的研究表明，NV在许多社区是地方性的，除了典型的暴发集群外，还引起散发性疾病。虽然发达国家的流行病学已经建立，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，缺乏对不同基因型的影响及其临床影响的了解， 没有细胞培养物或简单的动物模型用于该试剂。具体目标1。我们将通过基因组多个区域的基因分型来分析NV的母婴和家庭-儿童传播。我们将对秘鲁棚户区0-2岁儿童进行巢式病例对照研究。通过聚类分析将索引病例家族与两个年龄匹配的对照家族进行比较。我们将确定感染相同或不同NV基因型菌株的家庭成员的患病率。假设1.在指标病例家庭中，其他家庭成员NV感染的患病率高于对照家庭。假设2.一个孩子与母亲有相同的NV菌株的机会比其他家庭成员更大。假设3.大多数NV阳性的成年家庭成员将无症状。假设4.腹泻儿童的基因型不会在家庭其他成员中传播。具体目标2。我们将评估NV的特异性变异是否是儿童NV相关性腹泻严重程度或排泄时间的决定性因素。假设4.变异体将与腹泻的存在或严重程度相关。假设5.病毒载量和病毒排泄时间与特定基因组及其变异体相关。这项研究将涉及对NV的不同区域进行测序以进行分型，目的是确定是否存在对疾病严重程度或病毒在社区中传播的差异贡献。目前有多种引物可用于NV的测序，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。

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.