Department of Medical Laboratory Sciences, College of Health Sciences, Debre Tabor University, P.O. Box 272, Debre Tabor, Ethiopia.
Department of Medical Microbiology, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia.
Virol J. 2022 Jun 28;19(1):115. doi: 10.1186/s12985-022-01835-w.
Noroviruses are the leading cause of acute gastroenteritis in all age groups globally. The problem is magnified in developing countries including Africa. These viruses are highly prevalent with high genetic diversity and fast evolution rates. With this dynamicity, there are no recent review in the past five years in Africa. Therefore, this review and meta-analysis aimed to assess the prevalence and genetic diversity of noroviruses in Africa and tried to address the change in the prevalence and genetic diverisity the virus has been observed in Africa and in the world.
Twenty-one studies for the pooled prevalence, and 11 out of the 21 studies for genetic characterization of norovirus were included. Studies conducted since 2006, among symptomatic cases of all age groups in Africa, conducted with any study design, used molecular diagnostic methods and reported since 2015, were included and considered for the main meta-analysis. PubMed, Cochrane Library, and Google Scholar were searched to obtain the studies. The quality the studies was assessed using the JBI assessment tool. Data from studies reporting both asymptomatic and symptomatic cases, that did not meet the inclusion criteria were reviewed and included as discussion points. Data was entered to excel and imported to STATA 2011 to compute the prevalence and genetic diversity. Heterogeneity was checked using I test statistics followed by subgroup and sensitivity analysis. Publication bias was assessed using a funnel plot and eggers test that was followed by trim and fill analysis.
The pooled prevalence of norovirus was 20.2% (95% CI: 15.91, 24.4). The highest (36.3%) prevalence was reported in Ghana. Genogroup II noroviruses were dominant and reported as 89.5% (95% CI: 87.8, 96). The highest and lowest prevalence of this genogroup were reported in Ethiopia (98.3%), and in Burkina Faso (72.4%), respectively. Diversified genotypes had been identified with an overall prevalence of GII. 4 NoV (50.8%) which was followed by GII.6, GII.17, GI.3 and GII.2 with a pooled prevalence of 7.7, 5.1, 4.6, and 4.2%, respectively.
The overall pooled prevalence of norovirus was high in Africa with the dominance of genogroup II and GII.4 genotype. This prevalence is comparable with some reviews done in the same time frame around the world. However, in Africa, an in increasing trained of pooled prevalence had been reported through time. Likewise, a variable distribution of non-GII.4 norovirus genotypes were reported as compared to those studies done in the world of the same time frame, and those previous reviews done in Africa. Therefore, continuous surveillance is required in Africa to support future interventions and vaccine programs.
诺如病毒是导致全球各年龄段人群急性胃肠炎的主要原因。在包括非洲在内的发展中国家，这一问题更加严重。这些病毒具有高度流行、遗传多样性高和快速进化的特点。由于这种动态性，在过去五年中，非洲没有最近的综述。因此，本综述和荟萃分析旨在评估非洲地区诺如病毒的流行率和遗传多样性，并试图解决该病毒在非洲和世界范围内观察到的流行率和遗传多样性变化。
纳入了 21 项关于总流行率的研究，以及 21 项研究中的 11 项进行诺如病毒的遗传特征分析。研究对象为 2006 年以来非洲所有年龄段的有症状病例，采用任何研究设计，使用分子诊断方法，并于 2015 年以后报告，纳入并考虑进行主要荟萃分析。通过 PubMed、Cochrane 图书馆和 Google Scholar 检索获得研究。使用 JBI 评估工具评估研究质量。对同时报告有症状和无症状病例的研究进行了审查，这些研究不符合纳入标准，作为讨论点纳入。将数据输入到 excel 中，并导入到 STATA 2011 中以计算流行率和遗传多样性。使用 I 检验统计量检查异质性，然后进行亚组和敏感性分析。使用漏斗图和 eggers 检验评估发表偏倚，然后进行修剪和填充分析。
诺如病毒的总流行率为 20.2%（95%CI：15.91，24.4）。加纳的报告流行率最高（36.3%）。诺如病毒基因 II 组是主要的，报告为 89.5%（95%CI：87.8，96）。该基因组的最高和最低流行率分别在埃塞俄比亚（98.3%）和布基纳法索（72.4%）报告。已经确定了多样化的基因型，总体流行率为 GII.4 NoV（50.8%），其次是 GII.6、GII.17、GI.3 和 GII.2，流行率分别为 7.7%、5.1%、4.6%和 4.2%。
非洲地区诺如病毒的总流行率较高，以基因 II 组和 GII.4 基因型为主。这一流行率与同期全球进行的一些综述相当。然而，在非洲，随着时间的推移，报告的总流行率呈上升趋势。同样，与同期全球和非洲以往综述相比，报告的非 GII.4 诺如病毒基因型分布也存在差异。因此，需要在非洲进行持续监测，以支持未来的干预和疫苗计划。
