感染症と治療ジャーナル

抽象的な

Prevalence and Genetic Diversity of Human Norovirus Diarrhoea Among Children With Gastroenteritis in Africa: (Systematic Review and Meta-Analysis)

Sheriffo Jagne* Jarde Alexander, Nuredin Ibrahim Mohammed, Osbourne Quaye, Kwambana Adams Brenda, George Armah, Martin Antonio

Background Africa has the highest burden of norovirus associated gastroenteritis. This review aims to estimate norovirus prevalence and the distribution of circulating genogroups, genotypes and Gll.4 variants among children under 5 years with acute gastroenteritis in Africa. Methods A literature search was conducted using PubMed, biomed search.com, Ovid search, Cochrane and Popline. The inclusion criteria were study duration of at least 2months and diagnosis by RT-PCR . The data retrieved from articles included in this review included prevalence, sample size, norovirus positives, genotypes and genogroups. Data were computed for meta-analysis to estimate the prevalence and genetic diversity of norovirus among Africans children with acute gastroenteritis. Results The literature search containing Norovirus and Africa using the above stated databases produced 170 published articles. Out of the searched Human norovirus is associated with 18% (95% Cl: 17-20%) of diarrhoeal diseases and is one of the major causes of acute gastroenteritis in children worldwide. Noroviruses account for about one fifth of acute gastroenteritis cases in the world . Norovirus is an enteric virus known to play an important role in acute gastroenteritis in children. Noroviruses have been associated with the hospitalisation of children with acute gastroenteritis with the highest burden in children under five years of age. Noroviruses are small non-enveloped single stranded RNA viruses in the calciviridae family. It has a genome size of about 7.5kb, organised into three open reading frames (ORF) ORF1 to ORF3. The genome is highly liable to mutation and recombination which causes emergence of new strains and high genetic diversity in noroviruses . Noroviruses have different strains whose genome can easily recombine that could lead to diverse mixed infections. . Noroviruses are classified into six genogroups (GI-GVI) and genogroups GI, GII and GIV are known to infect humans. Among the genogroups that are known to infect humans, GII is the most predominant genogroup and also causes more than 70 articles, 33 articles from 15 countries met the inclusion criteria. Studies conducted in countries that did not meet the inclusion criteria were included in the discussion. The majority of the studies included in this review mainly focused on children less than 5 years of age hospitalized with acute gastroenteritis. Genotypic data from 15 countries revealed 31 genotypes and 13 Gll.4 variants with Sydney 2012 as the most common circulating variant across the continent. Norovirus genogroup 2 (Gll) and norovirus genotype Gll.4 had remained the most dominant genogroup and genotype detected in the majority of studies conducted.

Conclusion

Norovirus genogroup 2 (Gll), genotype Gll.4 and Sydney 2012 Gll.4 variant are commonly associated with childhood diarrhea in Africa however, only few studies were conducted within the region with limited data. The analysis revealed norovirus genetic diversity among genogroups, genotypes and variants. Norovirus surveillance should be implemented in Africa to assess the prevalence and genetic diversity of human noroviruses in children with acute gastroenteritis