Rotavirus types in Europe and their significance for vaccination

A Recombinant Rotavirus Antigen Based on the Coat Protein of Alternanthera Mosaic Virus

Thanks to their strong immunostimulating properties and safety for humans, plant viruses represent an appropriate basis for the design of novel vaccines. The coat protein of Alternanthera mosaic virus can form virus-like particles that are stable under physiological conditions and have adjuvant properties. This work presents a recombinant human rotavirus A antigen based on the epitope of rotavirus structural protein VP6, using Alternanthera mosaic virus coat protein as a carrier. An expression vector containing the gene of Alternanthera mosaic virus (MU strain) coat protein fused to the epitope of rotavirus protein VP6 was designed. Immunoblot analysis showed that the chimeric protein was effectively recognized by commercial polyclonal antibodies to rotavirus and therefore is a suitable candidate for development of a vaccine prototype. Interaction of the chimeric recombinant protein with the native coat protein of Alternanthera mosaic virus and its RNA resulted in the formation of ribonucleoprotein complexes that were recognized by anti-rotavirus antibodies.

Monitoring Shedding of Five Genotypes of RotaTeq Vaccine Viruses by Genotype-Specific Real-Time Reverse Transcription-PCR Assays

RotaTeq (RV5) is a widely used live attenuated pentavalent rotavirus (RV) vaccine. Although fecal shedding of RV vaccine strains persists for long time periods, it is unclear how each vaccine strain replicates in intestinal tissue and is excreted in stool. To examine this issue, we established RV5 genotype-specific real-time reverse transcription-PCR (RT-PCR) assays. Five real-time RT-PCR assays were designed for the VP7 gene in genotypes G1, G2, G3, G4, and G6. All assays exhibited excellent linearity, and the detection limit was 1 infectious unit (IU)/reaction for G2, G4, and G6 and 10 IUs/reaction for G1 and G3. No cross-reactivity was observed among G genotypes. The inter- and intra-assay coefficients of variation were less than 3%. The assays were used to examine 129 stool samples collected from eight infants who received RV5. In cases 1 and 2, who received three rounds of vaccination, RV shedding decreased gradually with the number of vaccinations. G1 and G6 shedding appeared to be predominant in comparison to shedding of the other genotypes. Patterns of fecal shedding of the five genotypes of vaccine viruses differed between the eight vaccine recipients. RV5 genotype-specific real-time RT-PCR assays will be useful to study the molecular biology of RV5 replication in infants and experimental animals.

Association of rotavirus strains and severity of gastroenteritis in Indian children

Rotavirus is the leading cause of severe and dehydrating diarrhea in children aged under 5 years. We undertook this hospital-based surveillance study to examine the possible relationship between the severity of diarrhea and the various G-group rotaviruses circulating in India. Stool samples (n = 2,051) were systematically collected from 4,711 children aged <5 years admitted with severe acute gastroenteritis to 12 medical school centers from April 2011 to July 2012. Rotavirus testing was undertaken using a commercially available enzyme immunoassay kit for the rotavirus VP6 antigen (Premier Rotaclone Qualitative ELISA). Rotavirus positive samples were genotyped for VP7 and VP4 antigens by reverse-transcription polymerase chain reaction at a central laboratory. Of the stool samples tested for rotavirus antigen, 541 (26.4%) were positive for VP6 antigen. Single serotype infections from 377 stool samples were compared in terms of gastroenteritis severity. Among those with G1 rotavirus infection, very severe diarrhea (Vesikari score ≥ 16) was reported in 59 (33.9%) children, severe diarrhea (Vesikari score 11–15) in 104 (59.8%), moderate (Vesikari score 6–10) and mild diarrhea (Vesikari score 0–5) in 11 (6.3%). Among those with G2 infection, very severe diarrhea was reported in 26 (27.4%) children, severe diarrhea in 46 (48.4%), and moderate and mild diarrhea in 23 (24.2 %). Among those with G9 infection, very severe diarrhea was reported in 47 (54.5%) children, severe diarrhea in 29 (33.6%), and moderate and mild diarrhea in 10 (11.9%). Among those with G12 infection, very severe diarrhea was reported in 9 (40.9%) children and severe diarrhea in 13 (59.1%). The results of this study indicate some association between rotavirus serotypes and severity of gastroenteritis.

Complete genome analysis of contemporary G12P[8] rotaviruses reveals heterogeneity within Wa-like genomic constellation

G12 rotaviruses are globally emergent rotaviruses causing severe childhood gastroenteritis. Little is known about the evolution and diversity of G12P[8] rotaviruses and the possible role that widespread vaccine use, globally, has had on their emergence. In Sicily, Italy, surveillance activity for rotaviruses has been conducted uninterruptedly since 1985, thus representing a unique observatory for the study of human rotaviruses in the pre- and post-vaccine era. G12 rotaviruses were first detected only in 2012 and between 2012 and 2014 they accounted for 8.7% of all rotavirus-associated infections among children, with peaks of 27.8% in 2012/2013 and 21% in 2014. We determined and analyzed the full-genome of 22 G12P[8] rotaviruses collected during the 2012-2014. Although all G12P[8] rotaviruses exhibited a typical Wa-like genotype constellation (G12P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1), phylogenetic analysis allowed distinguishing either two or three (sub)lineages in each genome segment. On the basis of the segregation patterns into lineages/sublineages, 20 G12P[8] rotaviruses could be grouped into three stable major genomic sub-constellations, whilst two strains displayed unique genome architectures, likely due to ressortment with co-circulating strains. Altogether, these findings indicate that the onset and prolonged circulation of G12 rotaviruses was due to repeated introductions of different G12 rotaviruses circulating globally. Importantly, as regional rotavirus vaccination was initiated in 2012 reaching a 45% coverage in newborns in 2014, a correlation between the appearance and spread of G12 rotaviruses and the enacted vaccination program could not be drawn. Constant epidemiologic surveillance remains important to monitor the epidemiological dynamics of human rotaviruses.

Rotavirus G2P[4] detection in fresh vegetables and oysters in Mexico City

Rotaviruses are the principal cause of dehydration caused by diarrhea in children younger than 2 years of age. Although these viral infections have mainly been associated with ingestion of fecally contaminated food and water, few studies have addressed the presence of the virus in food that is consumed raw or slightly cooked. In this work, 30 oyster samples and 33 vegetable samples were examined for the presence of rotavirus genotypes to evaluate their potential to produce gastrointestinal infections. The rotaviruses were identified by reverse transcriptase PCR amplification of the VP7 gene. G and P genotyping was also performed by reverse transcriptase PCR, with a detection sensitivity of up to 15 PFU/ml. Rotaviruses were found in 17 (26.9%) of 63 samples (10 oysters and 7 vegetables). The G2 genotype was found in 11 (64.7%) of 17 of the rotavirus strains, and 16 (94.1%) of 17 had the P[4] genotype. The combined genotypes found most frequently were G2P[4] (10 [58.82%] of 17), GNTP[4] (6 [35.29%] of 17), and G2P[NT] (1 [5.8%] of 17).

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.

Full genomic analysis of a human rotavirus G1P[8] strain isolated in South Korea

A rotavirus G1P[8] strain C1-81 was isolated from a 5-month-old female infant admitted to hospital with fever and severe diarrhea in Incheon, South Korea. To investigate its full genomic relatedness and its group, the full genome of strain C1-81 was determined. Based on a full genome classification system, C1-81 was shown to possess the typical Wa-like genotype constellation: G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. On the basis of sequence similarities, the strain was shown to be the closest related strain to contemporary human rotavirus strains with recent strains isolated in Asia. This C1-81 strain showed the highest degree of nucleic acid similarity (98.8% and 97%) to G1 B4633-03 and P[8] (Thai-1604 and Dhaka8-02), respectively. This is the first report that group A rotavirus was analyzed with G1P[8] in South Korea. The study of the complete genome of the virus will help understanding of the evolution of rotavirus.

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.

Prevalence and molecular genotyping of group a rotaviruses in Iranian children

Rotavirus is the leading cause of acute gastroenteritis in worldwide young children. Effective vaccines to prevent rotavirus infection are currently available, although their clinical use is still limited, and rotavirus still causes many episodes of infantile gastroenteritis, mainly during the winter season. The aim of this study was to evaluate the prevalence of rotavirus infection in children aged <5-years-old who were hospitalised for gastroenteritis. One hundred and sixty-three stool samples from hospitalised children (<5-years-old) complicated with severe diarrhoea, in two hospitals in Jahrom City, Iran were collected from 2009 to 2010. Antigenic prevalence of rotavirus group A was distinguished by enzyme immunoassay. The antigen of group A rotavirus was diagnosed by EIA in 75 of 163 collected samples. The genotype of EIA-positive samples was determined by nested RT-PCR. The frequency of rotavirus genotypes G1, G2, G3, G4 and G9 was 17.33, 13.34, 2.67, 30.66 and 2.67 %, respectively. Also, the frequency of mixed and non-typable genotypes was detected in 2.67 and 30.66 %, respectively. G1/G8 mixed infection was the first of these rotavirus genotypes to be reported in Iran. Detection of high prevalence of group A rotavirus infection in hospitalised children with diarrhoea, and determination of circulating rotavirus genotypes in this region of Iran, provide useful data for formulating effective vaccines; especially for infants less than 5-years-old.

Genotype diversity of group A rotavirus strains in children with acute diarrhea in urban Burkina Faso, 2008-2010

In this study, the diversity of G and P genotypes of rotavirus strains in Burkinabe children were examined. Between November 2008 and February 2010, 447 stool samples were collected from children <5 years of age with acute diarrhea visiting hospital in Ouagadougou. Group A rotavirus was previously detected in 151/447 (33.8%) of the samples tested by an immunochromatographic test and these samples were now tested further for rotavirus G and P genotypes by RT-PCR. Of these, the rotavirus type genes were amplified by RT-PCR for 140/151 (92.7%) samples and G and P genotypes were successfully determined for 81 (57.9%) and 130 (92.9%) samples, respectively. The most prevalent G genotypes were G1, 34/140 (24.3%), and G9, 21/140 (15%), while the predominant P genotypes were P[6], 56/140 (40%), and P[8], 54/140 (38.6%). Among the single infections, 63/140 (45%), the predominant G/P combinations were: G1P[8] (33%), G9P[8] (29%), and G2P[6] (14%). The unusual strains G1P[9] (3%), G12P[6] (3%), G10P[6] (2%), and G2P[8] (2%) were also detected. In a high number of strains 61/140 (43.6%), the G genotype could not be determined and mixed infections were determined in 17/140 (12.1%) of strains identified. This study highlights the high diversity and presence of unusual rotavirus strains in children in Burkina Faso.

Changing patterns of rotavirus genotypes in Turkey

To describe the circulation dynamics of human rotavirus genotypes and to understand the epidemiological changes of rotavirus infection in Turkey, one of the countries where the highest mortality rates are seen due to rotavirus in Europe. Stool samples of children under 5 years of age which gave positive results for rotavirus antigen were stored at -20°C and then genotyped using multiplex reverse transcription polymerase-chain reaction. Of the 494 stool samples, 137 (28.1%) were positive for rotavirus antigen and 100 (73%) samples which could be genotyped successfully were included in the study. 42 (42%) samples were from inpatients, and 58 (58%) were from outpatients. The median age of the children was 16 months (5 days-59 months). G9 and P[8] were the most frequent G and P genotypes, and were detected in 30 (30%) and 55 patients (55%), respectively. In 90 samples for which both G and P genotypes could be determined, 34 different combinations were found. G9P[8] was the most frequent genotype detected in 19 patients (19%), followed by G1P[8] and G4P[6] each in 7 (7%) patients. The incidence of mixed infection was found to be 26%. Novel strains like P2A[6] and P[5] and unusual reassortant strains were detected. Distribution of rotavirus genotypes exhibited distinctive changes in this study. When the ever-changing epidemiology of rotaviruses is taken into account, ongoing surveillance studies are important before the inclusion of rotavirus vaccines in national immunization program of Turkey.

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.

Primary care-based surveillance to estimate the burden of rotavirus gastroenteritis among children aged less than 5 years in six European countries

This observational, prospective study was undertaken to estimate the burden of rotavirus (RV) gastroenteritis (GE) leading to general practitioner (GP)/family paediatrician (FP) visits among children aged <5 years in Czech Republic, Germany, Italy, Poland, Spain and the UK. Children aged <5 years presenting with acute GE provided stool samples for rapid RV testing. RV+ samples were confirmed and typed by RT-PCR. Demographic and clinical data were collected for all RVGE episodes. Transmission patterns among other household children aged <5 years were also assessed. From November 2005 to May 2007, excluding data from the UK, 497/3,813 (13.0%) children aged <5 years presenting with acute GE to GP/FP and tested were RV+ by PCR. Most RVGE cases (69.1%) occurred in children aged <2 years, occurred between December and May (93.1%) and were moderate or severe by Vesikari score (92.9%). RV strain distribution varied between countries: G9P[8] was the most common type in Poland (54/76) and Spain (172/196), G1P[8] was predominant in the Czech Republic (56/64) and Italy (46/107), and G4P[8] and G1P[8] both prevailed in Germany (17/54 and 13/54, respectively). A total of 24/122 (19.7%) children aged <5 years resident in the same household as a PCR+ study participant also developed RVGE. Conclusion. This multinational epidemiological study in Europe shows that RV is easily transmitted among household children, with RVGE burden highest among children aged <2 years accessing primary healthcare for acute GE.

Epidemiology of rotavirus infection among young children with acute diarrhoea in Burkina Faso

BACKGROUND

In anticipation of vaccine introduction, we assessed epidemiology of rotavirus disease among children visiting medical centre due to acute diarrhoea in Ouagadougou, Burkina Faso.

METHODS

Between November 2008 and February 2010, stool specimens from 447 children less than 5 years of age suffering from diarrhoea were tested for the presence of rotavirus by antigen detection using an immunochromatographic test. Sociodemographic, environmental and clinical factors were assessed during the study.

RESULTS

Rotavirus antigen was detected in 151 (33.8%) of the patients. Most of the cases (94.2%) were in children < 24 months of age. Fever and vomiting were the symptoms most commonly reported in association with rotavirus diarrhoea and the patients were often hospitalized. Rotavirus-associated diarrhoea occurred mostly during the season from December to April (dry season). Rotavirus infection was significantly less frequent in breast-fed than among bottle-fed babies.

CONCLUSIONS

The results of this study underscore the need to control rotavirus infections among young children in Burkina Faso and may argue a decision on the introduction of rotavirus vaccine in Burkina Faso.

Epidemiological and clinical features of rotavirus among children younger than 5 years of age hospitalized with acute gastroenteritis in Northern Italy

BACKGROUND

Rotavirus is the major cause of acute gastroenteritis and severe dehydrating diarrhea in young children.

METHODS

To estimate the proportion of hospital admissions for rotavirus acute gastroenteritis and identify the circulating G and P genotypes among children under five years of age, we conducted a prospective observational study from January to December 2008, recruiting children consecutively admitted to six hospitals in Milan and nearby towns in northern Italy. Typing was done on stool samples by reverse transcriptase polymerase chain reaction amplification.

RESULTS

Of the 521 stool samples from children with acute gastroenteritis, 34.9% (95%CI, 30.8 to 39.2%) were rotavirus-positive. Two thirds (67.6%) were under two years of age, and 13.2% were under six months. The predominant G type was G1 (40.7%), followed by G9 (22.5%), G2 (13.2%), G3 (5.5%), G4 (3.8%) and G10 (1.6%). Twenty-one (11.7%) mixed-G infections were identified: G1+G10 (8.8%); G1+G9 (1.6%); and G2+G10 (1.2%). Only P[8] (67.6%) and P[4] (12.6%) types were P genotyped. The predominant single G/P combination was G1P[8] (39.7%), followed by G9P[8] (25.3%), G2P[4] (14.3%), and G3P[8] (4.1%). All G-mixed types combined with P[8].

CONCLUSIONS

These findings show an high prevalence of rotavirus infections among children admitted to hospital for acute gastroenteritis caused by different rotavirus strains circulating in the area studied.

Is it cost-effective to introduce rotavirus vaccination in the Dutch national immunization program?

This study assessed whether the inclusion of two rotavirus (RV) vaccines in the Dutch national immunization programme is cost-effective. Costs and outcomes in unvaccinated and vaccinated populations are compared for a time period of 20 years. In the baseline, assuming competitive market forces in relation to vaccine costs, Rotarix is more cost-effective than RotaTeq, resulting in a cost-utility ratio (CUR) of euro 53,000 per DALY (third payer perspective) and euro 49,000 per DALY (societal perspective), but both considered as being not cost-effective. Vaccine-related costs, annual epidemic-size, and indirect protection are the major factors that determine cost-effectiveness of RV vaccination.

Viral gastroenteritis

The virology, immunology, diagnosis, clinical symptoms, treatment, epidemiology and prevention measures relating to the most common viral causes of acute gastroenteritis (rotaviruses, human caliciviruses, astroviruses and enteric adenoviruses) are briefly reviewed. Uncommon viral causes of acute gastroenteritis and viruses causing gastroenteritis in immunodeficient patients are mentioned. The main change over the past three years has been the development, licensing and wide application of new live attenuated rotavirus vaccines.

G2P[4] the most prevalent rotavirus genotype in 2007 winter season in an European non-vaccinated population

BACKGROUND

Recently, a high prevalence of G2P[4] rotavirus (RV) infection was reported from Brazil, and linked with the universal RV vaccination programme that used the G1P[8] live oral RV vaccine.

OBJECTIVE

To determine the genotypes of RV co-circulating in a non-vaccinated population, in northern Portugal in the winter season of 2007.

STUDY DESIGN

Prospective multicenter study of the genotypes circulating in the northwest region of Portugal during January to March 2007. Children with acute gastroenteritis, who attended the Pediatric Emergency Services of five Hospitals, were included in the study. The parents of the children completed a clinical and epidemiological data questionnaire and stool samples were collected. Stool samples positive in a RV enzyme immunoassay (EIA) were genotyped by reverse transcriptase-polymerase chain reaction.

RESULTS

Stool samples were collected from 424 children. Two hundred and thirty-four (55.2%) stool samples were RV-positive. G2P[4] was the predominant RV type (68.6%), followed by G9P[8] (14.0%).

CONCLUSIONS

Because our population was naïve for RV vaccine, the G2P[4] predominance cannot be explained by vaccination. Rather, this high prevalence of G2P[4] may be within the normal fluctuation of RV genotypes. RV strain surveillance programmes are important for informing RV vaccination programmes.

Emergence of unusual human rotavirus strains in Salento, Italy, during 2006-2007

BACKGROUND

In recent years, rotavirus genotyping by RT-PCR has provided valuable information about the diversity of rotaviruses (RV) circulating throughout the world.The purpose of the present study was to monitor the prevalence of the different G and P genotypes of rotaviruses circulating in Salento and detect any uncommon or novel types.

METHODS

During the period from January 2006 to December 2007, a total of 243 rotavirus positive stool samples were collected from children with diarrhoea admitted to four Hospitals in the province of Lecce (Copertino, Galatina, Gallipoli and Tricase).All the specimens were tested for RV by real time PCR and genotyped for VP7 (G-type) and VP4 (P-type) gene by reverse transcription (RT) and multiplex PCR using different type specific primers.

RESULTS

In course of this study we identified 4 common G&P combinations viz. G2P[8], G1P[8], G2P[4] and G9P[8] amongst 59.8% of the typeable rotavirus positives.Rotavirus G2P[8] was recognized as the most widespread genotype during the sentinel-based survey in Salento.The detection of other novel and unusual strains, such as G2P[10], G4P[10], G8P[4], G9P[11] and G10P[8] is noteworthy.Furthermore, a significant number of mixed infections were observed during the survey period but G3P[8] rotaviruses were not detected.

CONCLUSION

This study highlights the genetic diversity among rotaviruses isolated from children in Salento and the emergence of some novel strains. Therefore, it is highly essential to continuously monitor for these strains so as to assess the impact of vaccines on RV strains circulating in Salento and understand the effect of strain variation on efficacy of presently available vaccines.

Hospital-based surveillance to estimate the burden of rotavirus gastroenteritis among European children younger than 5 years of age

OBJECTIVES

Rotavirus is the leading cause of acute gastroenteritis requiring hospitalization in young children. Data on the burden of rotavirus gastroenteritis are needed to guide recommendations for rotavirus vaccine use. This study was undertaken to estimate the burden of rotavirus gastroenteritis in European children <5 years of age.

METHODS

This prospective, study was conducted in 12 hospitals in France, Germany, Italy, Spain, and the United Kingdom. A sample of all children aged <5 years presenting to emergency departments or hospitalized because of community-acquired acute gastroenteritis was enrolled for parental interview and stool collection. Acute gastroenteritis was defined as diarrhea (>/=3 loose stools per 24 hours) for <14 days. Rotavirus was detected by enzyme-linked immunosorbent assay and typed by reverse-transcriptase polymerase chain reaction.

RESULTS

Between February 2005 and August 2006, 3734 children with community-acquired acute gastroenteritis were recruited and retained for analysis (55.9% via the emergency department, 41.8% hospitalized). Of the 2928 community-acquired acute gastroenteritis cases for which stool samples were available, 43.4% were rotavirus-positive by enzyme-linked immunosorbent assay (32.8% emergency department, 56.2% hospitalized). Of these rotavirus gastroenteritis cases 80.9% occurred in children aged <2 years and 15.9% among infants aged <6 months. Acute gastroenteritis was more severe in rotavirus-positive subjects (Vesikari score >/= 11 in 53.3% compared with 31.0% of rotavirus-negative subjects). All 1271 rotavirus-positive strains were genotyped (G1P[8]: 40.3%; G9P[8]: 31.2%; G4P[8]: 13.5%; G3P[8]: 7.1%).

CONCLUSIONS

Rotavirus gastroenteritis places high demands on European health care systems, accounting for 56.2% of hospitalizations and 32.8% of emergency department visits because of community-acquired acute gastroenteritis in children aged <5 years. Most community-acquired rotavirus gastroenteritis occurs in children aged <2 years, and a high proportion occurs in infants aged <6 months. Cases were also observed among very young infants <2 months of age. Rotavirus vaccination is expected to have a major impact in reducing morbidity and the pressure on hospital services in Europe.

Rotaviruses and rotavirus vaccines

BACKGROUND

Rotaviruses (RVs) are an important cause of acute gastroenteritis in infants and young children worldwide, resulting in more than 600 000 deaths per annum, mainly in developing countries. Since the 1980s, there has been intensive research on the development of RV vaccine candidates, and since 2006 two vaccines have been licensed in many countries.

SOURCES OF DATA

The scientific literature since the 1970s has been consulted, and the results of original research carried out in authors' laboratories were used.

AREAS OF AGREEMENT

There are firmly established data on virus particle structure, genome composition, gene-protein assignment, protein-function assignment (incomplete), virus classification, the mechanisms of several steps of the replication cycle (adsorption, primary transcription, virus maturation-all partial), several mechanisms of pathogenesis, aspects of the immune response, diagnosis, illness and treatment, epidemiology and vaccine development.

AREAS OF CONTROVERSY

Research on the following areas is still in full flux and in part not generally accepted: several steps of the replication cycle (mechanism of viral entry into host cells, mechanisms of packaging and reassortment of viral RNAs, morphogenesis of subviral particles in viroplasms and maturation of virus particles in the rough endoplasmic reticulum (RER) with temporary acquisition and subsequent loss of an envelope), the true correlates of protection and the long-term effectiveness of RV vaccines. GROWING RESEARCH: Recently, a system that allows carrying out reverse genetics with some of the RV genes has been established which, however, has limitations. There is intensive research ongoing, which is trying to develop better and universally applicable reverse genetics systems. There is broad research on the molecular mechanisms of the immune response and on which immunological parameter correlates best with lasting protection from severe RV disease. Research into other than live attenuated vaccines is growing.

AREAS TIMELY FOR DEVELOPING RESEARCH

The establishment of better reverse genetics systems for RVs is the most important research goal for both the understanding of the molecular biology of RVs and the development of new and safe RV vaccines. The black boxes of our knowledge on aspects of RV replication (RNA packaging, RNA replication, control of reassortment and functions of the non-structural RV proteins) are under intensive research.

Recommendations for the classification of group A rotaviruses using all 11 genomic RNA segments

Recently, a classification system was proposed for rotaviruses in which all the 11 genomic RNA segments are used (Matthijnssens et al. in J Virol 82:3204-3219, 2008). Based on nucleotide identity cut-off percentages, different genotypes were defined for each genome segment. A nomenclature for the comparison of complete rotavirus genomes was considered in which the notations Gx-P[x]-Ix-Rx-Cx-Mx-Ax-Nx-Tx-Ex-Hx are used for the VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5/6 encoding genes, respectively. This classification system is an extension of the previously applied genotype-based system which made use of the rotavirus gene segments encoding VP4, VP7, VP6, and NSP4. In order to assign rotavirus strains to one of the established genotypes or a new genotype, a standard procedure is proposed in this report. As more human and animal rotavirus genomes will be completely sequenced, new genotypes for each of the 11 gene segments may be identified. A Rotavirus Classification Working Group (RCWG) including specialists in molecular virology, infectious diseases, epidemiology, and public health was formed, which can assist in the appropriate delineation of new genotypes, thus avoiding duplications and helping minimize errors. Scientists discovering a potentially new rotavirus genotype for any of the 11 gene segments are invited to send the novel sequence to the RCWG, where the sequence will be analyzed, and a new nomenclature will be advised as appropriate. The RCWG will update the list of classified strains regularly and make this accessible on a website. Close collaboration with the Study Group Reoviridae of the International Committee on the Taxonomy of Viruses will be maintained.

Molecular characterization of bovine rotavirus strains circulating in northern Italy, 2003-2005

A total of 232 stools collected from calves with rotavirus infection in herds located in northern Italy from 2003 to 2005 was investigated. Determination of the rotavirus G and P types was carried out using nested RT-PCR. G6 was the most prevalent genotype, accounting for 78.5% of samples, G10 accounted for 9.9% of samples and viruses of G8 type were found in 4.7% of samples. In 3% of samples, viruses were not classified due to concomitant infection with more G type strains, whereas viruses in 3.9% of samples could not be characterized with any of the G-specific primers used in this study. Most common P types were P[11] and P[5], accounting for 65.1% and 25%, respectively. In 2.6% of cases, samples reacted with multiple P-specific primers; no P[1] serotype was identified. The G6P[11] combination was predominant throughout the study period, i.e. 52.5% in 2003, 50% in 2004 and 40% in 2005. The incidence of G6P[5] increased from 13.1% in 2003 to 27% in 2004 and 25.5% in 2005. The G10P[11] combination decreased markedly from 18% in 2003 to 2.6% in 2004, rising again to 7.3% in 2005. G8P[11] viruses were similarly present in 2003 (5%) and 2004 (4.3%), declining slightly in 2005 (1.8%).

Efficacy of human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in European infants: randomised, double-blind controlled study

BACKGROUND

We aimed to assess the efficacy of the oral live attenuated human rotavirus vaccine Rotarix (RIX4414) for prevention of rotavirus gastroenteritis in European infants during their first 2 years of life.

METHODS

3994 study participants were enrolled from six countries and were randomly assigned two oral doses of either RIX4414 (n=2646) or placebo (n=1348), which were coadministered with the first two doses of specific childhood vaccinations. Follow-up for gastroenteritis episodes was undertaken from 2 weeks post-dose two through the two consecutive rotavirus seasons following vaccinations (combined efficacy follow-up period; mean duration 17 months [SD 1.6]). Our primary endpoint was vaccine efficacy against rotavirus gastroenteritis of any severity during the first efficacy follow-up period (2 weeks post-dose two to the end of the first rotavirus season). Stool specimens obtained during gastroenteritis episodes were tested for rotavirus by ELISA and typed by RT-PCR. Episodes scoring 11 or greater on the 20-point Vesikari scale were classified as severe. Analysis was according to protocol. This study is registered with ClinicalTrials.gov, number NCT00140686 (eTrack102247).

FINDINGS

120 infants were excluded from the according-to-protocol analysis. During the first efficacy follow-up period (mean duration 5.7 months [SD 1.2]), 24 of 2572 infants allocated RIX4414 versus 94 of 1302 given placebo had rotavirus gastroenteritis episodes of any severity, resulting in a vaccine efficacy of 87.1% (95% CI 79.6-92.1; p<0.0001). For the combined efficacy follow-up period, vaccine efficacy against severe rotavirus gastroenteritis was 90.4% (85.1-94.1; p<0.0001), for admission owing to rotavirus gastroenteritis 96.0% (83.8-99.5; p<0.0001), and for rotavirus-related medical attention 83.8% (76.8-88.9; p<0.0001), and significant protection against severe rotavirus gastroenteritis by circulating G1, G2, G3, G4, and G9 rotavirus types was shown.

INTERPRETATION

In a European setting, two doses of RIX4414 coadministered with childhood vaccines provided high protection against any and severe rotavirus gastroenteritis, with an overall reduction of admissions for gastroenteritis over two consecutive rotavirus epidemic seasons.

Epidemiology of rotavirus in Portugal: G9 as a major cause of diarrhoea in non-hospitalised children

BACKGROUND

Rotavirus is a major cause of gastroenteritis in children worldwide, but there is no data available on the incidence of rotavirus gastroenteritis or on the strains circulating in Portugal.

METHODS

We determined prospectively the incidence of rotavirus infection in non-hospitalised children and the genotypes circulating during one winter season in the central region of Portugal.

RESULTS

Rotavirus was found in 45% of the samples tested. The peak incidence was in February (54% positive) and March (60% positive). Genotyping was performed in 195 samples; unexpectedly, G9P[8] was present in 90% of the cases, a much higher percentage than previously reported in other countries.

CONCLUSIONS

These results contribute to the assessment of the burden of disease attributable to rotavirus in Portugal and facilitate preparation for intervention by vaccination. The predominance of G9 in Portugal is unlikely to be a local phenomenon, and may be observed elsewhere in Portugal and Europe. The epidemiology of rotaviruses in Portugal should be monitored in subsequent years.

[Epidemiology of infectious acute diarrhoea in France and Europe]

Acute infectious diarrhoea can be linked to various pathogens among which viruses are responsible for more than a half cases. Rotaviruses and caliciviruses are the most frequently encountered, in close to 60 % of viral gastroenteritis. Rotaviruses account for more than 50 % of severe diseases and caliciviruses, especially norovirus are responsible for less severe sporadic gastroenteritis and water-or food- borne epidemics. Astroviruses and adenoviruses are minority, excepted for immunocompromised patients. Viral or Bacterial and viral co- infections are frequent (up to 15 %). To date, the first rotavirus vaccine assays did not reveal any shift from a viral genus to another, such as calicivirus or adenovirus, according to the fact that epidemiologic features of these viruses are quite different. Progress in viral diagnosis and genotyping enabled to analyse viral diversity and to follow viral recombination events, and emergence of new variants that could propagate among various countries. This dynamic evolution that concerns not only Europe but also developing countries should be carefully surveyed at the era of rotavirus vaccination.

Group A rotavirus genotypes in Germany during 2005/2006

During the 2005/2006 winter season a total of 802 group A positive rotavirus specimens of patients from different regions throughout Germany were genotyped. Amplicons from a one-tube RT-PCR were typed by analysis of their (type-specific) size using type-specific primers, fluorescent consensus primers and a capillary sequencer for detection. While G1P[8] was predominant (45.8%), G9P[8] has emerged as the second most frequent genotype combination (37.7%). The distribution of genotypes was heterogeneous, regional frequencies regarding G1 and G9 were ranging from 15.0 to 89.3% and from 7.1 to 67.7%, respectively. Furthermore, a few human rotavirus G10P[6] and G10P[8] infections were observed.

Molecular epidemiology of rotavirus in Central and Southeastern Europe

A surveillance network was implemented by the Istituto Superiore di Sanità of Rome in collaboration with laboratories of virology in Czech Republic, Slovenia, Croatia, Albania, and Bulgaria. About 1,500 rotavirus-positive stool samples were collected from children with severe gastroenteritis admitted to hospitals or outpatient wards between 2004 and 2006. The G and P genotypes were determined by reverse transcription-nested PCR. Significant differences were found in the geographical distributions of rotavirus genotypes between countries participating in the study. The prevalence of "common" G/P combinations, G1P[8], G3P[8], G4P[8], and G2P[4], ranged between 50 and 85%. The G9 genotype, which is emerging worldwide, was identified in 2 to 35% of all samples depending on the country. Unusual combinations, such as G1 or G4 associated with P[4] or G2 with P[8], which may have arisen by reassortment between human strains, were found in samples from 3 to 20% of patients. The uncommon genotypes G8P[8] and G10P[6], which may have an animal origin, were also identified. Double infections with two rotavirus strains were observed in between 1.7 and 14% of cases studied. Our findings might implicate challenges for rotavirus vaccine implementation in a wide geographic area of the Balkans and Central-Eastern Europe and underscore the importance of extensive strain surveillance for success in vaccine development.

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

In Spain, diarrhea remains a major cause of illness among infants and young children. To determine the prevalence of rotavirus genotypes and temporal and geographic differences in strain distribution, a structured surveillance study of hospitalized children <5 years of age with diarrhea was initiated in different regions of Spain during 2005. Rotavirus was detected alone in samples from 362 (55.2%) samples and as a coinfection with other viruses in 41 samples (6.3%). Enteropathogenic bacterial agents were detected in 4.9% of samples; astrovirus and norovirus RNA was detected in 3.2% and 12.0% samples, respectively; and adenovirus antigen was detected in 1.8% samples. Including mixed infections, the most predominant G type was G9 (50.6%), followed by G3 (33.0%) and G1 (20.2%). Infection with multiple rotavirus strains was detected in >11.4% of the samples studied during 2005.

Rotavirus vaccines: considerations for successful implementation in Europe

A group of European experts in infectious diseases and vaccinology has met on several occasions to assess the rationale for universal vaccination against rotavirus infection of infants in Europe. On the basis of the available data, we concluded that vaccination was the best approach to prevent severe rotavirus gastroenteritis, and that European countries should consider implementing rotavirus vaccination in their routine immunisation programmes. The main barrier to the implementation of rotavirus vaccination in Europe is a general lack of awareness of stakeholders, policymakers, health-care professionals, and parents about rotavirus disease and the advantages of vaccination. Further studies on the cost of the disease and the benefit of vaccination, together with raising awareness are necessary steps to ensure successful implementation of rotavirus vaccination in Europe.