Molecular epidemiology of noroviruses detected in Vietnamese children with acute gastroenteritis from 2012 to 2015

Abstract

Noroviruses, an important cause of diarrhoea in humans, are genetically diverse. The recent norovirus seasons recorded the emergence of new recombinants of the capsid and polymerase genotypes, with a global dominance of GII.Pe_GII.4 Sydney 2012 and GII.P17_GII.17 in Asian countries. However, the number of papers reporting the distribution of both polymerase and capsid genotypes circulating among children is scarce, with none from Vietnam. This study described both the polymerase and capsid genotypes of noroviruses circulating in Vietnamese children using stool specimens obtained under the World Health Organization rotavirus surveillance programme from 2012 to 2015. Of 350 specimens tested, noroviruses were detected in 90 (28 %) of 319 inpatient specimens and in 9 (29 %) of 31 outpatient specimens. The polymerase and capsid genotype combinations of GII.Pe_GII.4 Sydney 2012 and GII.P21_GII.3 were co-dominant (51 and 24 %, respectively), both of which were recombinants, contributing to a high proportion (87 %) of recombinants among circulating noroviruses. GII.4 variants evolved in the same fashion in Vietnam as in other countries, with amino acid substitutions in the putative variant-specific epitopes of the protruding domain. Unlike neighbouring countries where the predominance of GII.P17_GII.17 was reported, only one GII.P17_GII.17 strain was detected from an outpatient in 2015 in Vietnam. In conclusion, a substantial burden due to norovirus gastroenteritis hospitalizations among Vietnamese children was associated with circulating co-dominant GII.Pe_GII.4 Sydney 2012 and GII.P21_GII.3 strains. Continued surveillance is necessary to monitor infection caused by GII.4 variants and that of GII.P17_GII.17 noroviruses in paediatric patients in Vietnam.

Human Enteric Circulating Viruses and Co-infections Among Hospitalized Children with Severe Acute Gastroenteritis in Chihuahua, Mexico, During 2010 - 2011

“…Norovirus was identified in 3.5% of the analyzed samples with severe AGE, whereas other reports indicated a prevalence of 5.3% in Mexico (29). Despite this, different studies showed the prevalence of this pathogen to be up to 35.2% in sporadic outbreaks of acute gastroenteritis in children under five-years-old (30). Indeed, the GII genogroup has been found in up to 92% of the analyzed samples in other countries (30)(31)(32), which represents a latent risk due to this virus incidence increase among children younger than five-years-old after the application of the rotavirus vaccine (33).…”

“…Despite this, different studies showed the prevalence of this pathogen to be up to 35.2% in sporadic outbreaks of acute gastroenteritis in children under five-years-old (30). Indeed, the GII genogroup has been found in up to 92% of the analyzed samples in other countries (30)(31)(32), which represents a latent risk due to this virus incidence increase among children younger than five-years-old after the application of the rotavirus vaccine (33). Furthermore, the analysis revealed the presence of genotypes HAstV-1 and HAstV-3, indicating a high prevalence of astroviruses in this region, which is in line with reports from other countries (24,(34)(35)(36)(37).…”

Genetic Diversity and Epidemiology of Norovirus in Children with acute sporadic gastroenteritis in Shanghai, China, 2012-2017

“…The reason for this infection difference in diverse age groups was still ambiguous and further studies need to be conducted to explore the mechanism. [17,32,38,40,42].…”

Genetic Diversity and Epidemiology of Genogroup II Noroviruses in Children with Acute Sporadic Gastroenteritis in Shanghai, China, 2012-2017

“…The reason for this different susceptibility to infection between diverse age groups is still unclear, and further studies need to be conducted to explore the mechanism of this difference. [17,32,38,40,42].…”