Human rotavirus G9 and G3 as major cause of diarrhea in hospitalized children, Spain

Worldwide prevalence and genotype distribution of human astrovirus in gastroenteritis patients: A systematic review and meta-analysis

AIM

Human astrovirus (HAstV) is an important causative agent of gastroenteritis in humans, which mainly infects young children and the elderly. The goal of this study was to conduct a meta-analytic review of the prevalence of HAstV amongst patients with gastroenteritis, and to shed light on the connection between HAstV infection and gastroenteritis.

METHODS

Systematic literature searches were conducted to identify all potentially relevant studies recorded up to April 8th, 2022. For study weighting, the inverse variance method was employed and the random-effects model was applied to evaluate data. For case-control studies, the pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to establish the relationship between HAstV infection and gastroenteritis.

RESULTS

Among 302423 gastroenteritis patients from 69 different countries, the overall pooled prevalence of HAstV infection was 3.48% (95% CI: 3.11%-3.89%). Case-control approach was used in 39 investigations, and the overall prevalence of HAstV infection among the 11342 healthy controls was 2.01% (95% CI: 1.40%-2.89%). Gastroenteritis and HAstV infection were associated with a pooled OR of 2.16 (95% CI: 1.72-2.71; P < 0.0001; I² = 33.7%). The most commonly found HAstV genotypes in gastroenteritis patients were HAstV1 (62.18%), HAstV7 (33.33%), and HAstV-MLB1 (17.43%).

CONCLUSION

The frequency of HAstV infection was the highest in children under the age of five, and in developing countries. The prevalence rate of HAstV was not influenced by gender. Semi-nested and nested RT-PCR were highly sensitive assays for detecting HAstV infections.

Nonpharmaceutical interventions against the COVID-19 pandemic significantly decreased the spread of enterovirus in children

BACKGROUND

Precise prevention and control measures have been adopted to impede the transmission of COVID-19 in China. This study was performed to investigate the effect of protective measures on gastrointestinal infection in children during the COVID-19 pandemic.

METHODS

The data on the rotavirus and adenovirus antigen tests were collected in outpatient children due to gastroenteritis from January 1, 2019, to December 31, 2020, at the Children's Hospital of Zhejiang University School of Medicine. According to age and month distribution, the positive number and rate of rotavirus and adenovirus in 2020 were compared with 2019.

RESULTS

A 3.8-fold and 4-fold reduction in the number of rotavirus- and adenovirus-positive patients in 2020 were found, respectively. The overall positive rate of rotavirus and adenovirus infection was drastically decreased in 2020 (rotavirus 2020: 18.18% vs 2019: 9.75%, P < 0.001; adenovirus 2020: 3.13% vs 2019: 1.58%, P < 0.001). The proportions of rotavirus and adenovirus in all age groups in 2020 decreased compared with those in 2019. The highest frequency of rotavirus infection occurred among children aged 1-3 years both in 2019 and 2020 (2019: 27.95% vs 2020: 17.19%, P < 0.001), while adenovirus infection was detected in children aged 3-5 years, which had the highest percent positivity (2019: 8.19% vs 2020: 4.46%; P < 0.001). An obvious peak prevalence of rotavirus incidence was found during December-April, and the percent positivity of rotavirus significantly decreased in 2020 (December 2019: 24.26% vs 2020: 8.44%, P < 0.001; January 2019: 40.67% vs 2020: 38.18%, P < 0.05; February 2019: 40.73% vs 2020: 15.04%, P < 0.001; March 2019: 31.47% vs 2020: 7.88%, P < 0.001; April 2019: 15.52% vs 2020: 4.78%, P < 0.001). The positive rate of adenovirus distributed throughout 2019 was 1.91%-4.86%, while the percent positivity during 2020 in the same period was much lower (0.00%-3.58%).

CONCLUSIONS

Our results confirmed that the preventive and control measures adopted during the COVID-19 pandemic and the collateral benefit of these interventions have significantly decreased the transmission of rotavirus or adenovirus. This article is protected by copyright. All rights reserved.

Rotavirus disease and health care utilisation among children under 5 years of age in highly developed countries: A systematic review and meta-analysis

BACKGROUND

Rotavirus (RV) infection is the leading cause of diarrhoea-associated morbidity and mortality globally among children under 5 years of age. RV vaccination is available, but has not been implemented in many national immunisation plans, especially in highly developed countries. This systematic review aimed to estimate the prevalence and incidence of health care use for RV gastroenteritis (RVGE) among children aged under 5 years in highly developed countries without routine RV vaccination.

METHODS

We searched MEDLINE and Embase databases from January 1^st 2000 to December 17^th 2018 for publications reporting on incidence or prevalence of RVGE-related health care use in children below 5 years of age: primary care and emergency department (ED) visits, hospitalisations, nosocomial infections and deaths. We included only studies with laboratory-confirmed RV infection, undertaken in highly developed countries with no RV routine vaccination plans. We used random effects meta-analysis to generate summary estimates with 95% confidence intervals (CI) and prediction intervals.

RESULTS

We screened 4033 abstracts and included 74 studies from 21 countries. Average incidence rates of RVGE per 100 000 person-years were: 2484 (95% CI 697-5366) primary care visits, 1890 (1597-2207) ED visits, 500 (422-584) hospitalisations, 34 (20-51) nosocomial infections and 0.04 (0.02-0.07) deaths. Average proportions of cases of acute gastroenteritis caused by RV were: 21% (95% CI 16-26%) for primary care visits; 32% (25-38%) for ED visits; 41% (36-47%) for hospitalisations, 29% (25-34%) for nosocomial infections and 12% (8-18%) for deaths. Results varied widely between and within countries, and heterogeneity was high (I² > 90%) in most models.

CONCLUSION

RV in children under 5 years causes many healthcare visits and hospitalisations, with low mortality, in highly developed countries without routine RV vaccination. The health care use estimates for RVGE obtained by this study can be used to model RV vaccine cost-effectiveness in highly developed countries.

Intragenic recombination influences rotavirus diversity and evolution

Because of their replication mode and segmented dsRNA genome, homologous recombination is assumed to be rare in the rotaviruses. We analyzed 23,627 complete rotavirus genome sequences available in the NCBI Virus Variation database, and found 109 instances of homologous recombination, at least eleven of which prevailed across multiple sequenced isolates. In one case, recombination may have generated a novel rotavirus VP1 lineage. We also found strong evidence for intergenotypic recombination in which more than one sequence strongly supported the same event, particularly between different genotypes of segment 9, which encodes the glycoprotein, VP7. The recombined regions of many putative recombinants showed amino acid substitutions differentiating them from their major and minor parents. This finding suggests that these recombination events were not overly deleterious, since presumably these recombinants proliferated long enough to acquire adaptive mutations in their recombined regions. Protein structural predictions indicated that, despite the sometimes substantial amino acid replacements resulting from recombination, the overall protein structures remained relatively unaffected. Notably, recombination junctions appear to occur nonrandomly with hot spots corresponding to secondary RNA structures, a pattern seen consistently across segments. In total, we found strong evidence for recombination in nine of eleven rotavirus A segments. Only segments 7 (NSP3) and 11 (NSP5) did not show strong evidence of recombination. Collectively, the results of our computational analyses suggest that, contrary to the prevailing sentiment, recombination may be a significant driver of rotavirus evolution and may influence circulating strain diversity.

Study of Complete Genome Sequences of Rotavirus A Epidemics and Evolution in Japan in 2012-2014

A comprehensive molecular epidemiological study using next-generation sequencing technology was conducted on 333 rotavirus A (RVA)-positive specimens collected from six sentinel hospitals across Japan over three consecutive seasons (2012–2014). The majority of the RVA isolates were grouped into five genotype constellations: Wa-like G1P[8], DS-1-like G1P[8], G2P[4], G3P[8] and G9P[8]. Phylogenetic analysis showed that the distribution of strains varied by geographical locations and epidemic seasons. The VP7 genes of different G types were estimated to evolve at 7.26 × 10^-4–1.04 × 10^-3 nucleotide substitutions per site per year. The Bayesian time-scaled tree of VP7 showed that the time to the most recent common ancestor of epidemic strains within a region was 1–3 years, whereas that of the epidemic strains across the country was 2–6 years. This study provided, for the first time, the timeframe during which an epidemic strain spread locally and within the country and baseline information needed to predict how rapidly RVAs spread.

High prevalence of G3 rotavirus in hospitalized children in Rawalpindi, Pakistan during 2014

Rotavirus A species (RVA) is the leading cause of severe diarrhea among children in both developed and developing countries. Among different RVA G types, humans are most commonly infected with G1, G2, G3, G4 and G9. During 2003-2004, G3 rotavirus termed as "new variant G3" emerged in Japan that later disseminated to multiple countries across the world. Although G3 rotaviruses are now commonly detected globally, they have been rarely reported from Pakistan. We investigated the genetic diversity of G3 strains responsible RVA gastroenteritis in children hospitalized in Rawalpindi, Pakistan during 2014. G3P[8] (18.3%; n = 24) was detected as the most common genotype causing majority of infections in children less than 06 months. Phylogenetic analysis of Pakistani G3 strains showed high amino acid similarity to "new variant G3" and G3 strains reported from China, Russia, USA, Japan, Belgium and Hungary during 2007-2012. Pakistani G3 strains belonged to lineage 3 within sub-lineage 3d, containing an extra N-linked glycosylation site compared to the G3 strain of RotaTeqTM. To our knowledge, this is the first report on the molecular epidemiology of G3 rotavirus strains from Pakistan and calls for immediate response measures to introduce RV vaccine in the routine immunization program of the country on priority.

Molecular epidemiology and associated risk factors of rotavirus infection among children < 5 yrs hospitalized for acute gastroenteritis in North Eastern, Kenya, 2012

INTRODUCTION

Rotavirus is a leading cause of morbidity and mortality among children under five years worldwide. This study aimed to characterize the circulating genotypes of rotavirus and to determine risk factors of rotavirus infection in North Eastern, Kenya before the introduction of rotavirus vaccines.

METHODS

we conducted a cross sectional study among children < 5 years old hospitalized for acute gastroenteritis at the study hospital. Rotavirus was detected in stool specimens and further characterized using PAGE and RT-PCR. Socio-demographic and risk factor information was collected using a standard questionnaire.

RESULTS

we enrolled 237 children into the study hospitalized with acute gastroenteritis. Of these, 41 (17%) tested positive for group A rotavirus in stool specimens. Age < 2 years, unboiled tap water, underweight and low birth weight were identified as independent risk factors of rotavirus infection. Majority 8 (57%) of the detected rotavirus RNA profiles were long electropherotypes. G3, G9 and P4 were the predominant genotypes identified.

CONCLUSION

Rotavirus is an important aetiology of acute gastroenteritis among children under five years in this region. Risk factors common in other regions and rotavirus vaccine preventable genotypes are responsible for infection. We recommend the introduction of rotavirus vaccines, coupled with good infant nutrition, safe water supply and maternal hygienic practices during infant feeding.

Rotavirus infections in Detroit, USA, a region of low vaccine prevalence

After a sharp drop of rotavirus (RV) infections at Children's Hospital of Michigan, Detroit, USA in 2010 season, we noted an increase in the number of cases during the 2011 season including some RV vaccine (RVV) recipients. This study was conducted to determine the circulating genotypes during 2011 season and whether the increase in RV diarrhea was caused by replacement genotypes. G and P genotypes were determined by RT PCR and nucleotide sequencing of selected strains was performed. The vaccination rate among study patients was 24 %. RV strains from 68 stool samples were genotyped including 18 from vaccinated children and 50 from unvaccinated children. The predominant G genotype was G1 (58.8 %) followed by G9 (17.7 %) and G4 (15.5 %). P[8] was the predominant P genotype (68 %) followed by P[6] (17.6 %) and P[4] (3 %). All G9 strains were associated with P[6]. The most prevalent G-P combination was G1P[8] (56 %), followed by G9P[6] (17.6 %). Similar proportions of RV genotypes were found among vaccinated and unvaccinated children. Our local data suggest that 5 years after the introduction of RVV there has been no genotype replacement. Although a small increase in G9P[6] frequency was noted, G1P[8] remained the predominant strain of RV in our inner city community in the Midwestern USA.

The burden of norovirus disease in children in the European Union

BACKGROUND

Noroviruses (NoVs) are the leading cause of acute gastroenteritis across all age groups. Because a vaccine is in clinical development, burden of disease data are required to guide the eventual introduction of this vaccine. In this study, we estimate the burden of NoV disease in children less than 5 years of age in the European Union (EU).

METHODS

We carried out a literature search using PubMed to identify studies providing incidence or prevalence data for NoV disease in the EU. We applied the pooled average NoV incidence and prevalence rates to the EU population less than 5 years of age to obtain the annual number of NoV illnesses, medical visits, hospitalizations and deaths occurring in the EU among children younger than 5 years.

RESULTS

Data from 12 studies were included. We estimate that NoV infection may cause up to 5.7 million illnesses in the community, 800,000 medical visits, 53,000 hospitalizations and 102 deaths every year in children younger than 5 years in the EU.

CONCLUSION

The burden of NoV disease in children in the EU is substantial, and will grow in relative importance as rotavirus (RV) vaccines are rolled out in the EU. This burden of disease is comparable with the burden of RV disease in the EU before RV vaccine introduction. More country-specific studies are needed to better assess this burden and guide the potential introduction of a vaccine against NoV at the national level.

Rotavirus Diarrhea among Children in Taiz, Yemen: Prevalence-Risk Factors and Detection of Genotypes

Diarrheal diseases are a great public health problem; they are among the most causes leading to morbidity and mortality of infants and children particularly in developing countries and even in developed countries. Rotavirus is the most common cause of severe gastroenteritis in infants and young children in both developed and developing countries. The purpose of this study was to determine the incidence rate of Rotavirus infection, its genotypes, and risk factors among children with diarrhea in Taiz, Yemen. 795 fecal samples were collected from children (less than 5 years old), suffering from diarrhea and attending the Yemeni-Swedish Hospital (YSH) in Taiz , Yemen, from November 2006 to February 2008. Rotavirus was detected by enzyme linkage immunosorbent assay (ELISA) on stool specimens of children. Genotypes of Rotavirus were characterized by reverse transcriptase-polymerase chain reaction (RT-PCR) and polyacrylamide gel electrophoresis (PAGE). The results showed that 358 (45.2%) were Rotavirus-positive and the most prevalent genotypes were G2P[4] (55%), followed by G1P[8] (15%). In addition, Rotavirus was found through the whole year; however, higher frequency during the summer season (53.4%) and lower frequency during the winter season (37.1%).

Molecular epidemiology and genetic evolution of the whole genome of G3P[8] human rotavirus in Wuhan, China, from 2000 through 2013

BACKGROUND

Rotaviruses are a major etiologic agent of gastroenteritis in infants and young children worldwide. Since the latter of the 1990s, G3 human rotaviruses referred to as "new variant G3" have emerged and spread in China, being a dominant genotype until 2010, although their genomic evolution has not yet been well investigated.

METHODS

The complete genomes of 33 G3P[8] human rotavirus strains detected in Wuhan, China, from 2000 through 2013 were analyzed. Phylogenetic trees of concatenated sequences of all the RNA segments and individual genes were constructed together with published rotavirus sequences.

RESULTS

Genotypes of 11 gene segments of all the 33 strains were assigned to G3-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1, belonging to Wa genogroup. Phylogenetic analysis of the concatenated full genome sequences indicated that all the modern G3P[8] strains were assigned to Cluster 2 containing only one clade of G3P[8] strains in the US detected in the 1970s, which was distinct from Cluster 1 comprising most of old G3P[8] strains. While main lineages of all the 11 gene segments persisted during the study period, different lineages appeared occasionally in RNA segments encoding VP1, VP4, VP6, and NSP1-NSP5, exhibiting various allele constellations. In contrast, only a single lineage was detected for VP7, VP2, and VP3 genes. Remarkable lineage shift was observed for NSP1 gene; lineage A1-2 emerged in 2007 and became dominant in 2008-2009 epidemic season, while lineage A1-1 persisted throughout the study period.

CONCLUSION

Chinese G3P[8] rotavirus strains have evolved since 2000 by intra-genogroup reassortment with co-circulating strains, accumulating more reassorted genes over the years. This is the first large-scale whole genome-based study to assess the long-term evolution of common human rotaviruses (G3P[8]) in an Asian country.

Complete genome analysis of a rare human G3P[9] rotavirus posing as an AU-1 like strain

Background

We performed phylogenetic and sequence analysis by Basic Local Alignment Search Tool (BLAST) of a complete Human Rotavirus (HRV) genome isolated from a hospitalized child with acute gastroenteritis in Thailand.

Findings

The results indicated an uncommon strain characterized by multiple re-assortments in the VP3, VP4, VP6, NSP1, NSP4 and NSP5 genes. The uncommon strain is genotype G3-P[9]-I3-R3-C3-M3-A3-N3-T3-E3-H6, which displays aspects of the AU-1, FRV-1 and corresponds to the feline/canine prototype G3P[9] strain.

Conclusions

The results suggested that nearly all the eleven gene segments of G3P[9] RVA strain CU365 might have originated from feline/canine RVAs (Rotavirus A).

Monitoring of children with acute gastroenteritis in Madrid, Spain, during 2010-2011: rotavirus genotype distribution after the vaccines introduction

BACKGROUND AND OBJECTIVES

A structured surveillance study was conducted on children with diarrhea who were hospitalized in Madrid (Spain) during 2010-2011, in order to describe temporal, geographic, and age-related trends in rotavirus (RV) strains after the introduction of the RV vaccines in our country.

STUDY DESIGN AND RESULTS

A total of 370 children were enrolled, with RV being detected in 117 (31.6%) cases. Coinfections were detected mainly with rotavirus, astrovirus and norovirus. The most prevalent rotavirus G type was G1 (60.7%) followed by G2 (16.09%), G9 (5.9%), and G12 (5.1%). The G12 genotype appeared for the first time in 2008 in Spain, and it has increased to 5.1% of the cases in this report. Some uncommon P genotypes, such as P[14] and P[6], both with a low percentage, were found. The samples with G1 G2, G9 and G12 genotypes appeared in all ages, but were significantly higher in children under 2 years old.

CONCLUSION

A long-term structured surveillance is required in the Spanish post vaccine era, in order to determine the prevalence and variability of RV genotypes. This will especially be needed to distinguish between changes occurring as a result of natural fluctuation in genotype or those (changes) that could be mediated by population immunity to the vaccines. In addition, it will be necessary to study the impact of the current vaccines on the circulating rotavirus strains and on the overall reduction in the prevalence of rotavirus disease among children in Spain.

Detection and molecular characterization of diarrhea causing viruses in single and mixed infections in children: a comparative study between Bangladesh and Turkey

The incidence and mortality caused by diarrhea differ among countries. The prevalence of different enteric viruses, their molecular characteristics, and infections with multiple viruses might affect the disease incidence and mortality caused by diarrhea. The objective of this study was to determine the distribution and molecular characteristics of enteric viruses in children with diarrhea in Turkey and Bangladesh. A total of 288 stool samples that were negative for group A rotavirus were collected from children aged <5 years with acute diarrhea who presented to hospitals in Turkey and Bangladesh. The samples were screened for human bocavirus (HBoV), astrovirus (HAstV), norovirus (NoV), and adenovirus (AdV). Phylogenetic analyses of the targeted virus genes were performed. In Turkey, viruses were detected in 87/150 samples (58%), which included 69 (79.3%) with single viruses and 18 (20.7%) with multiple viruses. AdV was the most common virus, followed by HBoV. In Bangladesh, viruses were detected in 123/138 samples (89.1%), which included 29 (23.6%) with single viruses and 94 (76.4%) with multiple viruses. NoV GII was the most common, followed by AdV. The dominant genotypes among the virus species were HBoV 2A, HAstV 1, NoV GI type 1, and AdV 40. For NoV GII, the Hunter variant of genotype 4 in Turkey and genotype 17 in Bangladesh were the most common among the sequenced strains. It was concluded that the distribution of the viruses associated with diarrhea in Turkish and Bangladeshi children was different. Enteric viruses and mixed infections were more prevalent in Bangladesh than in Turkey.

Host genetic factors affect susceptibility to norovirus infections in Burkina Faso

Norovirus (NoV) constitutes the second most common viral pathogen causing pediatric diarrhea after rotavirus. In Africa, diarrhea is a major health problem in children, and yet few studies have been performed regarding NoV. The association of histo-blood group antigens (HBGA) and susceptibility to NoV infection is well established in Caucasian populations with non-secretors being resistant to many common NoV strains. No study regarding HBGA and NoV susceptibility has yet been performed in Africa. We collected 309 stool and 208 saliva samples from diarrheal children in Ouagadougou, Burkina Faso; May 2009 to March 2010. NoV was detected using real-time PCR, and genotyped by sequencing. Saliva samples were ABO, Lewis and secretor phenotyped using in house ELISA assays. NoV was detected in 12% (n = 37) of the samples. The genotype diversity was unusually large; overall the 37 positive samples belonged to 14 genotypes. Only children <2 years of age were NoV positive and the GII.4 NoVs were more frequent in the late dry season (Jan-May). NoV infections were observed less in children with the secretor-negative phenotype or blood group A (OR 0.18; p = 0.012 and OR 0.31; p = 0.054; respectively), with two non-secretors infected with genotypes GII.7 and GII.4 respectively. Lewis-negative (Le^a−b−) children, representing 32% of the study population, were susceptible to GII, but were not infected with any NoV GI. GII.4 strains preferentially infected children with blood group B whereas secretor-positive children with blood group O were infected with the largest variety of genotypes. This is the first study identifying host genetic factors associated with susceptibility to NoV in an African population, and suggests that while the non-secretor phenotype provides protection; the Lewis b antigen is not necessary for GII infection.

Molecular characterization of rotavirus isolates from select Canadian pediatric hospitals

BACKGROUND

We report the first multi-site rotavirus genotype analysis in Canada. Prior to this study, there was a dearth of rotavirus G and P genotyping data in Canada. Publically funded universal rotavirus vaccination in Canada started in 2011 and has been introduced by four provinces to date. Uptake of rotavirus vaccines in Canada prior to 2012 has been very limited. The aim of this study was to describe the genotypes of rotavirus strains circulating in Canada prior to widespread implementation of rotavirus vaccine by genotyping samples collected from selected paediatric hospitals. Secondly we identified rotavirus strains that differed genetically from those included in the vaccines and which could affect vaccine effectiveness.

METHODS

Stool specimens were collected by opportunity sampling of children with gastroenteritis who presented to emergency departments. Samples were genotyped for G (VP7) genotypes and P (VP4) genotypes by hemi-nested multiplex PCR methods. Phylogenetic analysis was carried out on Canadian G9 strains to investigate their relationship to G9 strains that have circulated in other regions of the world.

RESULTS

348 samples were collected, of which 259 samples were rotavirus positive and genotyped. There were 34 rotavirus antigen immunoassay negative samples genotyped using PCR-based methods. Over the four rotavirus seasons, 174 samples were G1P[8], 45 were G3P[8], 22 were G2P[4], 13 were G9P[8], 3 were G4P[8] and 2 were G9P[4]. Sequence analysis showed that all Canadian G9 isolates are within lineage III.

CONCLUSIONS

Although a limited number of samples were obtained from a median of 4 centres during the 4 years of the study, it appears that currently approved rotavirus vaccines are well matched to the rotavirus genotypes identified at these hospitals. Further surveillance to monitor the emergence of rotavirus genotypes in Canada is warranted.

Burden of community-acquired and nosocomial rotavirus gastroenteritis in the pediatric population of Western Europe: a scoping review

BACKGROUND

Rotavirus affects 95% of children worldwide by age 5 years and is the leading cause of severe dehydrating diarrhea. The objective of this review was to estimate the burden of rotavirus gastroenteritis (RVGE) in the Western European pediatric population.

METHODS

A comprehensive literature search (1999-2010) was conducted in PubMed and other sources (CDC; WHO, others). Data on the epidemiology and burden of RVGE among children < 5 years-old in Western Europe --including hospital-acquired disease--were extracted.

RESULTS

76 studies from 16 countries were identified. The mean percentage of acute gastroenteritis (AGE) cases caused by rotavirus ranged from 25.3%-63.5% in children < 5 years of age, peaking during winter. Incidence rates of RVGE ranged from 1.33-4.96 cases/100 person- years. Hospitalization rates for RVGE ranged from 7% to 81% among infected children, depending on the country. Nosocomial RVGE accounted for 47%-69% of all hospital-acquired AGE and prolonged hospital stays by 4-12 days. Each year, RVGE incurred $0.54- $53.6 million in direct medical costs and $1.7-$22.4 million in indirect costs in the 16 countries studied. Full serotyping data was available for 8 countries. G1P[8], G2P[4], G9P[8], and G3P[8] were the most prevalent serotypes (cumulative frequency: 57.2%- 98.7%). Serotype distribution in nosocomial RVGE was similar.

CONCLUSIONS

This review confirms that RVGE is a common disease associated with significant morbidity and costs across Western Europe. A vaccine protecting against multiple serotypes may decrease the epidemiological and cost burden of RVGE in Western Europe.

Prevalence of human rotavirus genotypes in Wuhan, China, during 2008-2011: changing trend of predominant genotypes and emergence of strains with the P[8]b subtype of the VP4 gene

Hospital-based surveillance of rotavirus genotypes was conducted in Wuhan, China, between March 2008 and May 2011. The detection rates of group A rotavirus were 24.6% (458/1859) and 12.1% (96/795) in children and adults, respectively, with diarrhea. Among the 554 positive specimens, the most frequent genotype was G3P[8] (57.9%), followed by G1P[8] (29.4%). Compared with previous studies in Wuhan (2000-2008), the relative frequency of G3P[8] has been decreasing year by year, while the predominant genotype G3 shifted to G1 in 2011. In the present study, a rare P[8]b subtype of the VP4 gene (OP354-like P[8]) was identified in nine strains. Full-length sequences of VP7, VP4, VP6 and NSP4 genes of two G9P[8]b strains (RVA/Human-wt/CHN/E1545/2009/G9P[8]b and RVA/Human-wt/CHN/Z1108/2008/G9P[8]b) were determined for phylogenetic analysis. The four genes of these strains were closely related to one another, and the G9-VP7 genes of these strains belonged to lineage III, which contains globally spreading G9 rotaviruses. The full-length sequence of VP4 gene segments of the P[8]b strains in Wuhan clustered with those of P[8]b strains in Vietnam, Russia and Belgium, while they were distinct from those of the OP354 strain from Malawi and Bangladeshi strains. The VP6 and NSP4 genes of two P[8]b strains belonged to the I1 and E1 genotype, respectively, and clustered with those of strains belonging to Wa-like human rotaviruses from various Asian countries. These findings indicate the changing epidemiologic trend of rotavirus genotypes in Wuhan, i.e., the shift of the predominant type from G3 to G1 and the emergence of P[8]b strains genetically related to those distributed in other Asian countries.

Molecular epidemiology and clinical characterization of group A rotavirus infections in Tunisian children with acute gastroenteritis

Rotaviruses are the most common cause of severe viral gastroenteritis in early childhood worldwide. Thus, the objectives of our study were to determine the molecular epidemiology and the clinical features of rotavirus gastroenteritis in Tunisia. Between January 2003 and April 2007, a prospective study was conducted on 788 stool samples collected from children under 12 years of age who were suffering from acute gastroenteritis. Rotavirus was detected by multiplex RT-PCR in 27% (n = 213) of samples, among them 79.3% (n = 169) cases were monoinfections. The frequency of rotavirus infections was significantly higher among inpatients (29%) than among outpatients (13%) (P < 0.001). The seasonal distribution of rotavirus diarrhea showed a winter peak, with an unusual peak from June to September. The mean duration of hospitalization was 6.5 ± 8.1 days and the mean age was 15.8 ± 22.8 months for rotavirus monoinfections. Fever, vomiting, abdominal pain, and dehydration were observed in 88, 98, 13, and 80 cases, respectively, in children with rotavirus monoinfections. G3P[8] (45.6%) and G1P[8] (23.9%) were the most common genotypes found in our study. The determination of rotavirus infection prevalence and the characterization of the rotavirus strains circulating will help us to better understand the molecular biology and epidemiology of the disease in our country.

High prevalence of community-acquired norovirus gastroenteritis among hospitalized children: a prospective study

Acute gastroenteritis (AGE) causes significant morbidity, especially in young children, and frequently requires hospitalization even in developed countries. Surveillance studies of AGE are important to determine the prevalence and variety of bacterial and viral pathogens, to initiate targeted preventive measures, such as vaccine programmes, and to monitor its impact. A prospective study was conducted in children <5 years old, admitted with AGE between April 2006 and April 2007 to the Virgen del Rocío University Hospital, Seville, Spain. Demographic and clinical data were collected and patients followed-up after hospital discharge. A stool sample from each child was screened for enteropathogenic bacteria and tested by reverse transcription polymerase chain reaction for rotavirus, astrovirus, norovirus and sapovirus and by the immunochromatographic method for enteric adenoviruses. Norovirus was the most common pathogen in hospitalized children, being detected in 27%, followed by rotavirus 21%. Mixed infection occurred in nearly 20% of all norovirus infections and was most commonly associated with Salmonella spp. Rotavirus infection was associated with an overall higher severe clinical score compared with norovirus infection. Lactose intolerance was observed in 29 children (7.5%) and most commonly due to rotavirus infection (p <0.001). Seizures were reported in four children. Norovirus was the commonest cause of AGE in hospitalized children <5 years during 2006-2007 in Seville, Spain. The use of these molecular techniques should be included routinely for the surveillance of sporadic cases and outbreaks of norovirus AGE in children attending hospitals as well as healthcare centres.

G2 as an emerging rotavirus strain in pediatric gastroenteritis in southern Italy

BACKGROUND

Human rotaviruses (HRVs) represent a major cause of acute gastroenteritis in children worldwide. It is estimated that they are responsible for a large number of diarrhea-associated hospitalizations in childhood each year. In Italy, limited data are available on the patterns of distribution of HRV G and P types. We report here the results of 2 years of rotavirus strain surveillance among children with severe gastroenteritis diagnosed in the town of Portici, Campania, southern Italy.

METHODS

A total of 421 stool specimens from children between 6 months and 5 years of age and presenting acute diarrhea were collected and tested by routine diagnostic tests for HRV, adenovirus, astrovirus, norovirus, and common bacterial pathogens.

RESULTS

The laboratory results showed that 110 of the 225 (26.1%) virus-positive samples contained HRVs. The different G and P rotavirus genotypes were analyzed by polymerase chain reaction (PCR). Among the VP7 genotypes identified, G1 and G2 were predominant, with percentages of 48.2 and 30.9%, respectively. G4, G9, and G10 were detected in a minority of cases. Among the VP4 genotypes, P[8] occurred the most frequently (56.4%), followed by P[4] (31.8%), and only a few P[10] and P[11] at percentages of 1.8 and 0.9%, respectively.

CONCLUSION

Our epidemiological data of HRV strains will contribute to assessing the magnitude of the problem of HRV in the south of Italy.

Emergence of human rotavirus genotype G9 in metropolitan Detroit between 2007 and 2009

Between January 2007 and April 2009, rotavirus (RV)-positive stool samples from 238 children with acute gastroenteritis, seen at Children's Hospital of Michigan in Detroit, USA, were collected and RV genotyping was performed. G and P genotypes were determined by RT-PCR and nucleotide sequencing was conducted on selected G9 and P[6] strains. Correlation between the severity of gastroenteritis episode and the infecting G genotype was done using a 14-point scoring system. The predominant G genotype was G9 (39.5 %), followed by G1 (35.3 %) and G4 (15.5 %), while P[8] was the most prevalent P genotype (66.5 %), followed by P[4] (21.9 %) and P[6] (11.2 %). The gene combinations G1P[8] and G9P[8] were the most prevalent (21.4 % and 20.6 %, respectively), followed by G4P[8] (13 %) and G9P[6] (8.8 %). Immunization data showed that only 17/238 (7.1 %) children received ≥one dose of RV vaccine (the pentavalent vaccine RotaTeq or the monovalent vaccine Rotarix) and that 10/17 were infected with G4P[8] strains. Severity of RV gastroenteritis episodes was not related to the infecting G genotype. Our results suggest a high proportion of genotype G9 strains in combination with P[8], P[6] and P[4] specificity circulating in the metropolitan Detroit area. While the protective efficacy of the RV vaccines has been demonstrated against G9P[8] strains, the level of cross-protection offered by the vaccines against G9 strains with P[6] and P[4] genotypes in the Detroit paediatric population remains to be determined.

Rotavirus disease and vaccination: impact on genotype diversity

Temporal and spatial fluctuations in the genotype distribution of human rotaviruses are continuously observed in surveillance studies. New genotypes, such as G9 and G12, have emerged and spread worldwide in a very short time span. In addition, reassortment events have the potential to contribute substantially to genetic diversity among human and animal rotaviruses. With the recent introduction of the two rotavirus vaccines, RotaTeq and Rotarix, in many countries, it appears that the total number of hospitalizations due to rotavirus infections is being reduced, at least in developed countries that implemented a universal immunization program. However, continued surveillance is warranted, especially regarding the long-term effects of the vaccines. No data analyses are available to clarify whether rotavirus vaccine introduction would allow other rotavirus P and G genotypes, which are not covered by the current vaccines, to emerge into the human population and fill the apparent gap. This kind of data analysis is essential, but its interpretation is hampered by natural and cyclical genotype fluctuations.

Incidence of hospitalization due to community-acquired rotavirus infection: a 12-year study (1996–2008)

The incidence of hospitalization for acute gastroenteritis (AGE) is a useful parameter to assess the utility of the new rotavirus vaccines in high-income countries. Children hospitalized for AGE were identified by searching hospital discharge data and the records of the microbiology laboratory of Hospital Donostia. Rotavirus antigen was investigated in 96·1% of the 1114 children aged 1 month to <5 years hospitalized for AGE in the study period. Nearly 40% were rotavirus positive (44·9% of the 798 children aged 1 month to <2 years), with G1[P8] being the predominant genotype. The mean annual incidence rate of hospitalization due to rotavirus AGE was 29·8 and 63·7 cases/10 000 inhabitants in the <5 and <2 years age groups, respectively, in 1996–1999, decreasing to 13·6 and 27·4 cases/10 000 inhabitants in <5 and <2 years age groups, respectively, in 2002–2005 (P<0·001). This decrease coincided with a significant increase in the consumption of oral rehydration solutions.

Nosocomial rotavirus gastroenteritis in Spain: a multicenter prospective study

BACKGROUND

The objective of this study was to assess the incidence of nosocomial rotavirus gastroenteritis among children <2 years of age.

METHODS

We conducted a prospective active surveillance for acute gastroenteritis (AGE) in the pediatric wards of 3 representative hospitals in Valencia (Spain) from October 2006 to March 2007, among children between 1 and 23 months of age with acute diarrhea. Children were followed up for 3 days after discharge. We obtained clinical and demographic information from participants and tested their stool specimens for rotavirus.

RESULTS

A total of 1576 children were hospitalized at the 3 hospitals and 1300 (82.5%) were followed up as the study cohort. In 69 children, AGE started 48 hours after admission and were considered nosocomial infections. In 35 of the 59 cases where stool samples were obtained, rotavirus (RV) was present (59%), and in 12 of them symptoms started after discharge. The accumulated incidence of nosocomial rotavirus disease during the study period was 2.8 cases per 100 inpatients (95% CI: 1.9-3.8), and the incidence rate was 4.8 cases per 1000 hospital days (95% CI: 3.2-6.5). The most commonly found genotype in nosocomial infection was G9P[8], in 23 cases (66%), followed by G1P[8] in 4 cases (11%). The total economic cost was 883 euro per case.

CONCLUSION

Active surveillance demonstrated that the burden of nosocomial rotavirus disease is substantial, and G9P [8] was the genotype found most frequently. Following up children after discharge from hospital allowed the discovery of cases of nosocomial RVAGE which are missed in most other studies.

Severity of acute gastroenteritis in infants infected by G1 or G9 rotaviruses

BACKGROUND

Group A rotaviruses are the main viral causative agent of acute diarrhea, and cause considerable morbidity in children. G9 rotaviruses have recently emerged all over the world and are thought to give more severe symptoms because of a lack of previous exposure and the absence of maternal antibodies in patients.

OBJECTIVES

To determine the clinical severity of G9 infections compared to G1 infections in hospitalized children.

STUDY DESIGN

The prospective study was conducted from 2004 to 2007 in French children under 5 years old hospitalized for acute gastroenteritis. The rotaviruses were detected in stools by ELISA tests and genotyped by RT-PCR on the basis of their outer capsid proteins. The duration of hospitalization, the Vesikari clinical score, and the requirement for intravenous rehydration were compared.

RESULTS

The stools from 370 children were analyzed and 162 stools infected by G1 (n=76) or G9 (n=86) rotaviruses were analyzed. Age and gender distribution were similar in the two groups as was the mean duration of hospitalization (2.7 days). The Vesikari scores were 12.96 and 12.83 in G1P[8] and G9P[8] groups (p=0.417), respectively, in which 55.3 and 53.5% of the children, respectively, were rehydrated with an intravenous line.

CONCLUSIONS

No difference in severity was found between G1 and G9 rotavirus infections. Rigorous surveillance to monitor changes in the ecology of rotavirus infections is necessary, as emerging strains are more likely to cause severe gastroenteritis and not respond to current rotavirus vaccines.

Prevalence and clinical characteristics of norovirus gastroenteritis among hospitalized children in Spain

BACKGROUND

The importance of norovirus as a cause of gastroenteritis outbreaks is well documented, but the role of norovirus in sporadic acute severe gastroenteritis is not so well established. The aim of this study was to determine the prevalence and clinical characteristics of norovirus gastroenteritis among hospitalized children.

METHODS

A prospective study was conducted in children less than 5 years old, admitted with acute gastroenteritis between January 2005 and January 2008 to the Pediatrics Department of the Universitary Hospital, Albacete, Spain. Demographic and clinical data were collected. A stool sample from each child was screened for enteropathogenic bacteria and tested by reverse transcription polymerase chain reaction for rotavirus, astrovirus, norovirus, and sapovirus and by immunochromatographic method for enteric adenoviruses.

RESULTS

Norovirus was the second most frequent pathogen after rotavirus, being detected in 61 (17.3%) of the 352 children enrolled, in 29 of them (8.2%) as single agent. Mixed infections involving other viruses or bacteria were present in 52.4% of norovirus positive samples, a nosocomial source of infection was demonstrated in 17.2%. Norovirus infection was more prevalent in winter and affected mainly children less than 2 years of age. Vomiting was present in 68% and fever in 48.3% of cases, 3 children had nonfebrile seizures. Compared with rotavirus enteritis, norovirus infection was slightly less severe (in terms of severity score and need of intravenous rehydration) and fever was less frequent.

CONCLUSIONS

Norovirus was a frequent cause of acute severe sporadic gastroenteritis in children representing the second etiologic agent after rotavirus.

Diversity of the G3 genes of human rotaviruses in isolates from Spain from 2004 to 2006: cross-species transmission and inter-genotype recombination generates alleles

Rotavirus evolves by using multiple genetic mechanisms which are an accumulation of spontaneous point mutations and reassortment events. Other mechanisms, such as cross-species transmission and inter-genotype recombination, may be also involved. One of the most interesting genotypes in the accumulation of these events is the G3 genotype. In this work, six new Spanish G3 sequences belonging to 0-2-year-old patients from Madrid were analysed and compared with 160 others of the same genotype obtained from humans and other host species to establish the evolutionary pathways of the G3 genotype. The following results were obtained: (i) there are four different lineages of the G3 genotype which have evolved in different species; (ii) Spanish G3 rotavirus sequences are most similar to the described sequences that belong to lineage I; (iii) several G3 genotype alleles were reassigned as other G genotypes; and (iv) inter-genotype recombination events in G3 viruses involving G1 and G2 were described. These findings strongly suggest multiple inter-species transmission events between different non-human mammalian species and humans.

The ever-changing landscape of rotavirus serotypes

Rotavirus is a double-stranded RNA virus that is characterized by substantial genetic diversity. The various serotypes of rotavirus have been determined by the presence of neutralizing epitopes on the outer capsid of the protein shell. At present, 5 rotavirus serotypes (G1, G2, G3, G4, G9) are the predominant circulating strains, accounting for approximately 95% of strains worldwide, although there is considerable geographic variability. Incidence rates for various serotypes also vary temporally with seasonal and year-to-year fluctuations. Unusual serotypes are generally uncommon, but new serotypes can emerge. In particular, G9[P8], a reassortment virus, was first identified in 1983 and in the last 10 to 15 years has become widely distributed worldwide. Indeed, G9[P8] has become highly prevalent in many countries in Europe and Australia, with somewhat lower incidence rates in South America, Africa, and Asia. The heterogeneity and ever-changing epidemiology of rotavirus underscores the need for continued surveillance to ensure that vaccination programs provide optimal protection.

[Detection of a rotavirus G9P[8] outbreak causing gastroenteritis in a geriatric nursing home]

INTRODUCTION

The aim of this study was to describe an outbreak of gastroenteritis due to rotavirus in a geriatric nursing home.

METHOD

Stool samples from 8 patients were studied. Antigen detection was carried out by ELISA, and molecular typing was performed by RT-PCR.

RESULTS

Rotavirus antigen was detected in 6 patients. Typing demonstrated a common genotype (G9P[8]).

CONCLUSION

The outbreak detected in elderly persons suggests a loss of immunity with age or a lack of protection against an emergent genotype.

Identification of risk factors associated with nosocomial infection by rotavirus P4G2, in a neonatal unit of a tertiary-care hospital

A rotavirus outbreak in newborns admitted to the 'La Paz' University Hospital, Madrid was detected, followed up and controlled. Uninfected children were selected as control subjects. Samples of faeces were taken once or twice weekly from all the newborns, including those who were asymptomatic and who were admitted to the neonatal unit for early detection of rotavirus and the positive were separated from the rest of the neonates. Contact-related precautions were taken for all patients, and alcohol solutions were used for hand washing. During the months of the outbreak, 1773 children were admitted to the hospital, 131 of whom were affected by the rotavirus infection (7.4%). Of these, 72 (55%) had symptomatic infections. In the first month of the outbreak, nine cases of necrotizing enterocolitis were diagnosed (one patient developed massive intestinal necrosis). The infections (symptomatic and asymptomatic) presented a bimodal distribution caused by a new outbreak of rotavirus type P4G2 after two patients who had acquired the infection outside the hospital were admitted when the first outbreak was subsiding. The characteristics of cases and controls were analysed using bivariate and multivariate methods (non-conditional multivariate logistic regression) to identify four risk factors strongly associated with rotavirus infection: premature birth, infections other than rotavirus, malformation, and changes in glycaemia and/or presence of jaundice.

Coinfection of viral agents in Korean children with acute watery diarrhea

Currently, there are a few reports on viral coinfection that causes an acute watery diarrhea in Korean children. So, to evaluate the features of coinfectious viral agents in children with acute watery diarrhea, we enrolled 155 children with acute watery diarrhea from July 2005 to June 2006. Fecal samples were collected and evaluated for various viral infections such as rotavirus, norovirus, adenovirus and astrovirus. The mean (+/-standard deviation) age of the children was 2.71+/-2.37 yr. The detection rate of viral agents was most common in children between the ages of 1 and 3 yr. Rotavirus was detected in 63 children (41.3%), norovirus in 56 (36.2%), adenovirus in 11 (7.1%), and astrovirus in 1 (0.6%). Regarding rotavirus, there were 38 (60.3%) cases with monoinfection and 25 (39.7%) with coinfection. For norovirus, there were 33 (58.9%) cases with monoinfection and 23 (41.1%) with coinfection. Coinfection with rotavirus and norovirus was most common, and occurred in 20/155 cases (12.9%) including coinfection with adenovirus. So, rotavirus and norovirus were the most common coinfectious viral agents in our study population with acute watery diarrhea.