Unexpected substitution of dominant rotavirus G genotypes in French hospitalized children over five consecutive seasons

Distribution of rotavirus genotypes in three Croatian regions among children ≤5 years of age (2012-2014)

OBJECTIVES

Rotavirus is the major cause of severe diarrhea in young children worldwide. In countries like Croatia, where rotavirus vaccine has not been introduced in the national immunization program, prospective surveillance is necessary to establish the diversity of rotavirus strains. The aim of this study was to describe the prevalence and geographical distribution of rotavirus strains in Croatia and to detect the possible emergence of novel strains.

METHODS

The study was conducted among children ≤5 years of age with acute gastroenteritis at three hospitals located in different geographical regions of Croatia, during the years 2012 to 2014. Rotavirus was detected in stools using an immunochromatographic assay and then sent for further molecular analysis.

RESULTS

Genotyping of 822 rotaviruses showed that the predominant circulating strain was G1P[8] (61.9%), followed by G2P[4] (19.5%), G1P[4] (3.9%), and G3P[8] (2.9%). A high prevalence of reassortants among common human rotavirus genotypes was detected (7.7%). Possible zoonotic reassortants were found, including G8 and G6 strains. The latter is described for the first time in Croatia.

CONCLUSIONS

This study represents pre-vaccination data that are important for decisions regarding immunization strategies in Croatia. The high prevalence of 'common' rotavirus strains circulating in Croatia may advocate for rotavirus vaccine introduction, but further surveillance is necessary to monitor the possible emergence of novel genotypes.

Detection and sequencing of rotavirus among sudanese children

INTRODUCTION

Diarrheal diseases are a big public health problem worldwide, particularly among developing countries. The current study was conducted to detect and characterize group A rotavirus among admitted children with gastroenteritis to the pediatric hospitals, Sudan.

METHODS

A total of 755 stool samples were collected from Sudanese children with less than 5 years of age presenting with acute gastroenteritis during the period from April to September 2010. Enzyme-linked immunosorbent assay (ELISA) was used to Detection of Rotavirus antigens. Ribonucleic acid (RNAs) were extracted from rotavirus-positive stool samples using (QIAamp® Viral RNA Mini Kit). (Omniscript® Reverse Transcription kit) was used to convert RNA to complementary Deoxyribonucleic acid (cDNA). The cDNAs were used as template for detection of VP4-P (P for Protease-sensitive) and VP7-G (G for Glycoprotein) genotyping of Rotavirus using nested PCR and sequencing.

RESULTS

Out of the 755 stool samples from children with acute gastroenteritis, 121 were positive for rotavirus A. Among 24 samples that were sequenced; the VP7 predominant G type was G1 (83.3%), followed by G9 (16.7%). Out of these samples, only one VP4 P[8] genotype was detected.

CONCLUSION

As a conclusion the VP7 predominant G type was G1, followed by G9 whereas only one VP4 genotype was detected and showed similarity to P[8] GenBank strain. It appears that the recently approved rotavirus vaccines in Sudan are well matched to the rotavirus genotypes identified in this study, though more studies are needed.

Clinical severity and molecular characteristics of circulating and emerging rotaviruses in young children attending hospital emergency departments in France

Group A rotavirus (RVA) is the leading cause of acute gastroenteritis in young children worldwide. A prospective surveillance network has been set up to investigate the virological and clinical features of RVA infections and to detect the emergence of potentially epidemic strains in France. From 2009 to 2014, RVA-positive stool samples were collected from 4800 children <5 years old attending the paediatric emergency units of 16 large hospitals. Rotaviruses were then genotyped by RT-PCR with regard to their outer capsid proteins VP4 and VP7. Genotyping of 4708 RVA showed that G1P[8] strains (62.2%) were predominant. The incidence of G9P[8] (11.5%), G3P[8] (10.4%) and G2P[4] (6.6%) strains varied considerably, whereas G4P[8] (2.7%) strains were circulating mostly locally. Of note, G12P[8] (1.6%) strains emerged during the seasons 2011-12 and 2012-13 with 4.1% and 3.0% prevalence, respectively. Overall, 40 possible zoonotic reassortants, such as G6 (33.3%) and G8 (15.4%) strains, were detected, and were mostly associated with P[6] (67.5%). Analysis of clinical records of 624 hospitalized children and severity scores from 282 of them showed no difference in clinical manifestations or severity in relation to the genotype. The relative stability of RVA genotypes currently co-circulating and the large predominance of P[8] type strains may ensure vaccine effectiveness in France. The surveillance will continue to monitor the emergence of new reassortants that might not respond to current vaccines, all the more so as all genotypes can cause severe infections in infants.

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.

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.

The unpredictable diversity of co-circulating rotavirus types in Europe and the possible impact of universal mass vaccination programmes on rotavirus genotype incidence

This article reviews the incidence of group A rotavirus (RV) types isolated from children with acute gastroenteritis (AGE) in European countries during the last 5-10 years, with the aim of establishing an overview of RV diversity before the introduction of universal mass vaccination (UMV) programmes against RV disease in most European countries. Consistent with findings from previous surveys, a high degree of diversity of co-circulating RV types exists in different locations of Europe, and over different RV seasons. Whilst RV UMV can potentially change the diversity of co-circulating genotypes, there are at present insufficient data for Europe to come to firm conclusions. Even in countries outside Europe, with several years of RV surveillance following the introduction of RV UMV (Brazil, Australia, USA), it is not clear whether changes observed in the diversity of particular RV types are due to natural fluctuations or immunological pressure exerted by RV UMVs. Consequently, it will be very difficult for European countries that have RV UMVs to conclude whether incidence changes of RV types in children with AGE are driven by immune pressures from vaccination or simply reflect natural temporal and spatial fluctuations. Whilst the monitoring of co-circulating RV strains should be continued, it should be acknowledged that the licensed monovalent and pentavalent RV vaccines are similarly effective in developed countries and that levels of RV type-specific neutralising antibodies after RV vaccination are only partially correlated with the degree of protection achieved; therefore, the significance of RV diversity for RV vaccination may be less important than is often assumed.

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.

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.

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.

Molecular and clinical characterization of rotavirus from diarrheal infants admitted to pediatric emergency units in france

BACKGROUND

rotaviruses are the major cause of acute gastroenteritis in young children worldwide, and require careful surveillance, especially in the context of vaccination programs. Prospective surveillance is required to monitor and characterize rotavirus infections, including viral and clinical data, and to detect the emergence of potentially epidemic strains.

METHODS

between 2006 and 2009, stool samples and clinical records were collected from 2044 children with acute diarrhea admitted to the pediatric emergency units of 13 French university hospitals. Rotaviruses were detected in stools, then genotyped by reverse transcription-polymerase chain reaction with regard to their outer capsid proteins VP4 and VP7.

RESULTS

the genotyping of 1947 rotaviruses showed that G1 (61.7%) and G9 (27.4%) strains were predominant and stable, followed by G2 (6.5%), G3 (4.0%), and G4 (2.5%) strains. Most strains were associated with P[8] (92.9%). Overall, 31 uncommon strains and possible zoonotic reassortants were detected including G12 and G8 strains, some being closely related to bovine strains. No difference in clinical presentation and severity was found among genotypes.

CONCLUSIONS

the relative stability of rotavirus genotypes currently cocirculating in France may ensure vaccine effectiveness in the short and medium term. However, the likely emergence of G12 and G8 strains should be monitored during ongoing and future vaccination programs, especially as all genotypes can cause severe infections. Special attention should be paid to the emergence of new rotavirus reassortants not included in current rotavirus vaccines.

Epidemiology and clinical features of gastroenteritis in hospitalised children: prospective survey during a 2-year period in a Parisian hospital, France

Rotavirus is recognised as the most important agent of severe acute gastroenteritis (AGE) in young children. In a 2-year prospective survey, we investigated the epidemiology and clinical features of the viral and bacterial pathogens in children hospitalised for AGE. The study was performed in a Parisian teaching hospital from November 2001 to May 2004. Clinical data were prospectively collected to assess the gastroenteritis severity (20-point Vesikari severity score, the need for intravenous rehydration, duration of hospitalisation). Stools were systematically tested for group A rotavirus, norovirus, astrovirus and adenovirus 40/41, sapovirus and Aichi virus and enteropathogenic bacteria. A total of 457 children (mean age 15.9 months) were enrolled. Viruses were detected in 305 cases (66.7%) and bacteria in 31 cases (6.8%). Rotaviruses were the most frequent pathogen (48.8%), followed by noroviruses (8.3%) and adenoviruses, astroviruses, Aichi viruses and sapoviruses in 3.5%, 1.5%, 0.9% and 0.4%, respectively. Cases of rotavirus gastroenteritis were significantly more severe than those of norovirus with respect to the Vesikari score, duration of hospitalisation and the need for intravenous rehydration. Rotaviruses were the most frequent and most severe cause in children hospitalised for AGE, and noroviruses also account for a large number of cases in this population.

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.

Molecular characteristics of German G8P[4] rotavirus strain GER1H-09 suggest that a genotyping and subclassification update is required for G8

A rare G8P[4] rotavirus, designated GER1H-09, was detected in a stool sample from an infant suffering from repeated episodes of emesis for 2 days without diarrhea. Sequencing of all genomic RNA segments was performed, and complete coding sequences were determined. The VP7 amino acid sequence revealed a close phylogenetic relationship to human G8P[6] and G8P[8] isolates from Slovenia and Africa. GER1H-09 shared typical amino acid residues within variable regions VR3 to VR7 with those strains, and their subclassification as lineage G8-II rotaviruses is proposed. The variability in VR3 was identified as the likely reason for the failure in genotyping G8-II rotaviruses by commonly used multiplex PCR. Furthermore, the sequences of associated structural and nonstructural proteins showed high amino acid identities to DS-1-like rotaviruses. The genotype composition of GER1H-09 (G8-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2) suggests the occurrence of reassortment events between G8 genotypes and human DS-1-like G2P[4] rotaviruses.

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.

[Sensitivity and specificity of the VIKIA Rota-Adeno immuno-chromatographic test (bioMérieux) and the ELISA IDEIA Rotavirus kit (Dako) compared to genotyping]

The performances of two diagnostic tests for rotavirus infection in stool samples were evaluated during a prospective study in children of less than 36 months in child-care centers of Lyon from November 2004 to May 2005. The VIKIA Rota-Adeno immuno-chromatographic test (bioMérieux) and the ELISA IDEIA Rotavirus kit (Dako) were compared with a referral method, the genotyping. Fifty-seven stool samples were collected and analyzed by RT-PCR. The virus genome was detected in 29 samples. The most frequent genotypic combinations were G9P[8] with a prevalence of 75.9%. Sensitivity and specificity of the VIKIA Rota-Adeno test and the ELISA IDEIA Rotavirus kit were strictly comparable and very good: 96.6% (83.0; 99.9) and 96.4% (81.6; 99.9), respectively. The immuno-chromatographic technique were in concordance with the ELISA tests in 93.6% of cases. Thus, the VIKIA Rota-Adeno test is a good alternative for the occasional analysis of stool samples in ambulatory practice.