Biomedical Research Center, Qatar University, Doha 2713, Qatar.
Pediatric Emergency Center, Hamad Medical Corporation, Doha 3050, Qatar.
Viruses. 2019 Apr 29;11(5):400. doi: 10.3390/v11050400.
Norovirus (NoV) is recognized as the second most important etiological agent leading to acute gastroenteritis globally. In order to determine the burden and characteristics of NoV infections in children in Qatar, profiling of circulating genotypes and their correlation with demographics and clinical manifestations were evaluated.
A total of 177 NoV-positive fecal samples were collected from children suffering from acute gastroenteritis (AGE) during two-year period between June 2016 and June 2018. The age of the subjects ranged between 3 months and 12 years (median of 15 months). Genotyping was performed by amplifying and sequencing parts of viral VP1 and RNA-dependent RNA polymerase (RdRp) regions. Phylogenetic analysis and evolutionary relationships were performed using MEGA7.0. Fisher's exact test was used to run statistical analysis for the clinical and demographical characteristics of circulating strains.
Overall, NoV infections were relatively higher in males than females with a ratio of 1.3:1 ( = 0.0073). Most of the NoV infections were reported in children between 1 and 3 years old (49.7%), followed by those <1 and >3 years of age (41.2% and 9.1%, respectively). NoV infections occurred throughout the year, with a noticeable increase in summer (36.6%) and drop in winter (25.4%). Nearly all (98.8%) NoV-infected children were positive for genogroup II (GII) compared to only two samples (1.2%) being positive for genogroup I (GI): GI.3 and GI.4. NoV genotype GII.4 (62.2%), GII.2 (15.8%), and GII.3 (13.5%) were predominant in our study. The detected strains shared >98% sequence homology with emerging recombinant strain of GII.P16-GII.4/RUS/Novosibirsk/2017 (MG892929), GII.P16-GII.4 Sydney/2012 (KY887601), GII.4 Sydney/2012, recombinant GII.P4 New Orleans /2009/GII.4 Sydney 2012 (MG585810.1), and the emerging strain GII.P16-GII.2 CHN/2017 (MH321823). Severe clinical illness (vesikari score >10) was reported in children infected with genotypes sharing homology with the above emerging strains. While GII.4 was reported in all age groups, NoV GII.3 infections were higher in children <1 year of age. Both genogroups (GII.4 and GII.3) in addition to GII.2 reported higher incidence in Qatari subjects compared to other nationalities ( = 0.034).
This is the first report about NoV molecular epidemiology in Qatar. The most detected NoV strain was genogroup GII, which is the dominant genotype in the Middle East region. Further, we report GII.4, GII.2, and GII.3 as the most predominant NoV genotypes in our study. Moreover, disease severity scores were higher among children genotyped with genogroup GI (GI.4) and genogroup GII (GII.4, GII.2, GII.3, GII.6, and GII.7).
诺如病毒（NoV）被认为是导致全球急性肠胃炎的第二大重要病原体。为了确定卡塔尔儿童中诺如病毒感染的负担和特征，对循环基因型及其与人口统计学和临床表现的相关性进行了分析。
在 2016 年 6 月至 2018 年 6 月的两年期间，共收集了 177 份患有急性肠胃炎（AGE）的儿童粪便样本。研究对象的年龄在 3 个月至 12 岁之间（中位数为 15 个月）。通过扩增和测序病毒 VP1 和 RNA 依赖性 RNA 聚合酶（RdRp）区域的部分序列进行基因分型。使用 MEGA7.0 进行系统发育分析和进化关系分析。Fisher 精确检验用于对循环株的临床和人口统计学特征进行统计分析。
总体而言，男性的诺如病毒感染率高于女性，比例为 1.3:1（ = 0.0073）。大多数诺如病毒感染发生在 1 至 3 岁的儿童中（49.7%），其次是<1 岁和>3 岁的儿童（分别为 41.2%和 9.1%）。诺如病毒感染全年发生，夏季（36.6%）显著增加，冬季（25.4%）下降。几乎所有（98.8%）诺如病毒感染的儿童均为基因 II 型（GII）阳性，而仅有两个样本（1.2%）为基因 I 型（GI）阳性：GI.3 和 GI.4。在我们的研究中，诺如病毒基因型 GII.4（62.2%）、GII.2（15.8%）和 GII.3（13.5%）占主导地位。检测到的菌株与新兴重组株 GII.P16-GII.4/RUS/Novosibirsk/2017（MG892929）、GII.P16-GII.4 Sydney/2012（KY887601）、GII.4 Sydney/2012、重组 GII.P4 New Orleans /2009/GII.4 Sydney 2012（MG585810.1）和新兴株 GII.P16-GII.2 CHN/2017（MG321823）具有>98%的序列同源性。与上述新兴株具有同源性的基因型感染的儿童出现严重临床疾病（Vesikari 评分>10）。虽然 GII.4 存在于所有年龄组中，但 GII.3 感染在<1 岁的儿童中更为常见。与其他国籍相比（ = 0.034），除 GII.2 外，GII.4 和 GII.3 这两种基因型在卡塔尔人群中的发病率更高。
这是卡塔尔首次关于诺如病毒分子流行病学的报告。最常见的诺如病毒株是基因 II 型，它是中东地区的主要基因型。此外，我们报告 GII.4、GII.2 和 GII.3 是我们研究中最主要的诺如病毒基因型。此外，基因 GI（GI.4）和基因 GII（GII.4、GII.2、GII.3、GII.6 和 GII.7）的基因型感染儿童的疾病严重程度评分更高。
