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

Phylodynamics of G4P[8] and G2P[4] strains of rotavirus A isolated in Russia in 2017 based on full-genome analyses

Rotavirus A is a dynamically evolving pathogen causing acute gastroenteritis in children during the first years of life. In the present study, we conducted a phylodynamic analysis based on the complete sequences of 11 segments of rotaviruses with the G4P[8] and G2P[4] genotypes isolated in Russia in 2017. Since rotavirus has a segmented genome, our analysis was performed using the Bayesian approach based on separate samples of nucleotide sequences for each gene of the strains studied. For the strain with the genotype G4P[8], the most likely geographical locations of the nearest common ancestor were Russia (VP7, VP4, VP6), China (VP1), Thailand (VP3), Belgium (NSP1), Hungary (VP2, NSP2, NSP3), Italy (NSP4) and Japan (NSP5). For the strain with the G2P[4] genotype, India (VP7, VP4, VP6, NSP1, NSP4), Malawi (VP2, NSP2, NSP3), Australia (VP1), Italy (NSP5) and Bangladesh (VP3). The closest common ancestor of the strain with the genotype G4P[8] circulated in 2001-2012, depending on the gene being analyzed. For the strain with the G2P[4] genotype, the closest common ancestor dates from 2006 to 2013.

Impact of rotavirus vaccination on rotavirus genotype distribution and diversity in England, September 2006 to August 2016

IntroductionRotavirus vaccination with the live-attenuated monovalent (a G1P[8] human rotavirus strain) two-dose Rotarix vaccine was introduced in England in July 2013. Since then, there have been significant reductions in rotavirus gastroenteritis incidence.AimWe assessed the vaccine's impact on rotavirus genotype distribution and diversity 3 years post-vaccine introduction.MethodsEpidemiological and microbiological data on genotyped rotavirus-positive samples between September 2006 and August 2016 were supplied by EuroRotaNet and Public Health England. Multinomial multivariable logistic regression adjusting for year, season and age was used to quantify changes in genotype prevalence in the vaccine period. Genotype diversity was measured using the Shannon's index (H') and Simpson's index of diversity (D).ResultsWe analysed genotypes from 8,044 faecal samples. In the pre-vaccine era, G1P[8] was most prevalent, ranging from 39% (411/1,057) to 74% (527/709) per year. In the vaccine era, G1P[8] prevalence declined each season (35%, 231/654; 12%, 154/1,257; 5%, 34/726) and genotype diversity increased significantly in 6-59 months old children (H' p < 0.001: D p < 0.001). In multinomial analysis, G2P[4] (adjusted multinomial odds ratio (aMOR): 9.51; 95% confidence interval (CI): 7.02-12.90), G3P[8] (aMOR: 2.83; 95% CI: 2.17-3.81), G12P[8] (aMOR: 2.46; 95% CI: 1.62-3.73) and G4P[8] (aMOR: 1.42; 95% CI: 1.02-1.96) significantly increased relative to G1P[8].ConclusionsIn the context of reduced rotavirus disease incidence, genotype diversity has increased, with a relative change in the dominant genotype from G1P[8] to G2P[4] after vaccine introduction. These changes will need continued surveillance as the number and age of vaccinated birth cohorts increase in the future.

Investigation of Rotavirus with Various Methods in Children with Acute Gastroenteritis and Determination of Its Molecular Epidemiology in Kayseri Province, Turkey

BACKGROUND

In this study, the fresh stool samples from 254 children under 5 years of age with acute gastroenteritis which were delivered between October 2012 and December 2013 were collected.

METHODS

In the stool samples, rotavirus antigens were investigated using two different immunochromatographic methods which are routinely used at different times, namely the RIDA^® QUICK Rotavirus/Adenovirus Combi Test (R-Biopharm AG, Germany) and the Genx^® Rotavirus Test (Diamed-Lab, Turkey), in addition to the Rotavirus Ag (Stool) ELISA (DRG, Germany) kit. The results were compared with reverse transcriptase PCR (RT-PCR).

RESULTS

When the Genx^® Rotavirus Test and RIDA^® QUICK Rotavirus/Adenovirus Combi Test immunochromatographic methods were compared with RT-PCR, their sensitivity and specificity were found as 97.1%, 100%, and 80.4%, 72%, respectively. As to the Rotavirus Ag (Stool) ELISA method, on the other hand, its sensitivity was found to be 95.1% and its specificity was 86.5%. The most common genotype was G9P[8] (40%), which was followed by the G1P[8] (18.7%) and G3P[8] (9.6%) genotypes.

CONCLUSION

Consequently, it was revealed that the sensitivity of ELISA and immunochromatographic methods, which provide results in a short time and are used in the investigation of rotavirus antigen, was high and their specificity was low; further studies to determine the distribution of G and P genotypes will contribute to establishing strategies for vaccine development for rotavirus in the world.

Group A rotavirus and norovirus display sharply distinct seasonal profiles in Belém, northern Brazil

Several viruses have been associated with acute gastroenteritis (AGE), and group A rotavirus (RVA) and norovirus (NoV) are the most prevalent. This study aimed to assess their prevalence among children hospitalised for diarrhoea during a three-year surveillance study. From May 2008-April 2011, overall positivity rates of 21.6% (628/2904) and 35.4% (171/483) were observed for RVA and NoV, respectively. The seasonality observed indicated distinct patterns when both viruses were compared. This finding may explain why hospitalisation for AGE remains constant throughout the year. Continuous AGE monitoring is needed to better assess the patterns of infection.

Review of global rotavirus strain prevalence data from six years post vaccine licensure surveillance: is there evidence of strain selection from vaccine pressure?

Comprehensive reviews of pre licensure rotavirus strain prevalence data indicated the global importance of six rotavirus genotypes, G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]. Since 2006, two vaccines, the monovalent Rotarix (RV1) and the pentavalent RotaTeq (RV5) have been available in over 100 countries worldwide. Of these, 60 countries have already introduced either RV1 or RV5 in their national immunization programs. Post licensure vaccine effectiveness is closely monitored worldwide. This review aimed at describing the global changes in rotavirus strain prevalence over time. The genotype distribution of the nearly 47,000 strains that were characterized during 2007-2012 showed similar picture to that seen in the preceding period. An intriguing finding was the transient predominance of heterotypic strains, mainly in countries using RV1. Unusual and novel antigen combinations continue to emerge, including some causing local outbreaks, even in vaccinated populations. In addition, vaccine strains have been found in both vaccinated infants and their contacts and there is evidence for genetic interaction between vaccine and wild-type strains. In conclusion, the post-vaccine introduction strain prevalence data do not show any consistent pattern indicative of selection pressure resulting from vaccine use, although the increased detection rate of heterotypic G2P[4] strains in some countries following RV1 vaccination is unusual and this issue requires further monitoring.

Hospital-based surveillance to estimate the burden of rotavirus gastroenteritis in children below five years of age in Romania

INTRODUCTION

Rotavirus (RV) is a leading cause of acute gastroenteritis (AGE), affecting 95% of children below five years of age.

METHODS

In this prospective, multi-center study, children below five years of age who were hospitalized or those who visited the emergency room (ER) due to AGE or who developed AGE at least 48 hours after hospitalization (nosocomial infection) and had a RV-positive stool sample were included (n=1,222). RV-positive samples were genotyped by reverse-transcriptase polymerase chain reaction.

RESULTS

RV test results were available for 1,212 children (hospitalizations [n=677], ER visits [n=398] and nosocomial AGE cases [n=137]). Proportions of rotavirus gastroenteritis (RVGE) hospitalizations and ER visits were 51.70% (350/677; 95%CI: 47.86-55.52) and 36.18% (144/398; 95%CI: 31.45-41.12), respectively. Overall, 45.95% (494/1075) of all community-acquired AGE cases were due to RV. High numbers of RVGE cases were recorded between January and March. Most common genotypes were G9P[8] (34.27%) followed by G4P[8] (25.83%) and G1P[8] (23.02%). Of all community-acquired RVGE cases, the highest number of cases was observed in children aged 12-23 months. Median duration of hospitalization among RV-positive subjects was six days (range: 2-31 days). Incidence of nosocomial RVGE was 0.52 (95%CI: 0.45-0.60) cases per 1,000 child-days hospitalization. Median duration for additional hospitalization due to nosocomial RVGE was five days (range: 1-10). The highest burden of nosocomial RVGE was observed in children aged 12-23 months (42.34%, 58/137). Our findings confirm a high burden of acute RVGE disease in Romania and provide useful data to support the implementation of RV vaccination in Romania.

TRIAL REGISTRATION

NCT01253967.

Diagnosis of viral gastroenteritis in children: interpretation of real-time PCR results and relation to clinical symptoms

Molecular methods such as real-time polymerase chain reaction (PCR) are rapidly replacing traditional tests to detect fecal viral pathogens in childhood diarrhea. This technique has now increased the analytical sensitivity so drastically that positive results are found in asymptomatic children, leading to complex interpretation of real-time PCR results and difficult distinction between asymptomatic shedding and etiological cause of disease. We performed a review of the literature including pediatric studies using real-time PCR and a minimal inclusion period of one year to exclude bias by seasonality. We searched for studies on rotavirus, norovirus, adenovirus, astrovirus, and sapovirus, known to be the most common viruses to cause gastroenteritis in the pediatric population. For these viruses, we summarized the detection rates in hospitalized and community-based children with clinical symptoms of gastroenteritis, as well as subjects with asymptomatic viral shedding. Moreover, insight is given into the different viral sero- and genotypes causing pediatric gastroenteritis. We also discuss the scoring systems for severity of disease and their clinical value. A few published proposals have been made to improve the clinical interpretation of real-time PCR results, which we recapitulate and discuss in this review. We propose using the semi-quantitative measure of real-time PCR, as a surrogate for viral load, in relation to the severity score to distinguish asymptomatic viral shedding from clinically relevant disease. Overall, this review provides a better understanding of the scope of childhood gastroenteritis, discusses a method to enhance the interpretation of real-time PCR results, and proposes conditions for future research to enhance clinical implementation.

Screening of viral pathogens from pediatric ileal tissue samples after vaccination

In 2010, researchers reported that the two US-licensed rotavirus vaccines contained DNA or DNA fragments from porcine circovirus (PCV). Although PCV, a common virus among pigs, is not thought to cause illness in humans, these findings raised several safety concerns. In this study, we sought to determine whether viruses, including PCV, could be detected in ileal tissue samples of children vaccinated with one of the two rotavirus vaccines. A broad spectrum, novel DNA detection technology, the Lawrence Livermore Microbial Detection Array (LLMDA), was utilized, and confirmation of viral pathogens using the polymerase chain reaction (PCR) was conducted. The LLMDA technology was recently used to identify PCV from one rotavirus vaccine. Ileal tissue samples were analyzed from 21 subjects, aged 15–62 months. PCV was not detected in any ileal tissue samples by the LLMDA or PCR. LLMDA identified a human rotavirus A from one of the vaccinated subjects, which is likely due to a recent infection from a wild type rotavirus. LLMDA also identified human parechovirus, a common gastroenteritis viral infection, from two subjects. Additionally, LLMDA detected common gastrointestinal bacterial organisms from the Enterobacteriaceae, Bacteroidaceae, and Streptococcaceae families from several subjects. This study provides a survey of viral and bacterial pathogens from pediatric ileal samples, and may shed light on future studies to identify pathogen associations with pediatric vaccinations.

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.

Evolution of DS-1-like human G2P[4] rotaviruses assessed by complete genome analyses

Group A rotaviruses (RVAs) are a leading cause of viral gastroenteritis in children, with G2P[4] RVA being one of the most common human strains worldwide. The complete genome sequences of nine G2P[4] RVA strains, selected from a 26-year archival collection (1985-2011) established in Palermo, Italy, were determined. A strain associated with a peak of G2P[4] RVA activity in 1996 resembled a reassortant strain identified in Kenya in 1982 and differed completely in genomic make up from more recent strains that circulated during 2004-2011. Conversely, the 2004-2011 G2P[4] RVAs were genetically more similar to contemporary RVA strains circulating globally. Recent G2P[4] strains possessed either single or multiple genome segments (VP1, VP3 and/or NSP4) likely derived from ruminant viruses through intra-genotype reassortment. Amino acid substitutions were selected and maintained over time in the VP7 and VP8* antigenic proteins, allowing the circulation of two contemporary G2P[4] variants to be distinguished. Altogether, these findings suggest that major changes in the genomic composition of recent G2P[4] RVAs occurred in the early 2000s, leading to the appearance of a novel variant of the DS-1-like genotype constellation. Whether the modifications observed in the neutralizing antigens and in the genome composition of modern G2P[4] RVAs may affect the long-term effectiveness of the vaccination programmes remains to be explored.

Rotavirus epidemiology before and after vaccine introduction

OBJECTIVES

To evaluate the prevalence and circulation of rotavirus genotypes before and after the introduction of oral vaccine against human rotavirus, and to check for a possible change in the age of occurence of the infection by RV-A.

METHODS

This was a cross-sectional study conducted between 2002-2011, in the city of Juiz de Fora, state of Minas Gerais, Brazil. A total of 1,144 diarrheal stool specimens were obtained from nonhospitalized children aged between 0 and 5 years, and analyzed by polyacrylamide gel electrophoresis and reverse-transcription polymerase chain reaction for genotype characterization. Data on prevalence and age distribution of rotavirus cases were analyzed through the chi-squared test (p < 0.05), using SPSS, release 13.0.

RESULTS

Rotavirus infection was detected in 9.35% (107/1,144) samples, with prevalence rates ranging from 11.12% (90/809) in the pre-vaccine to 5.07% (17/335) in the post-vaccine period (p = 0.001). Among the samples tested, the most frequently detected genotypes were G1P[6] (6/33 = 18.2%) in the period between 2002 and 2005 and G2P[4] in 2006 (11/33 = 33.3%) and in the period between 2007 and 2011 (5/33 = 15.2%). There was also a significant reduction in the number of cases of rotavirus disease in children aged between 0 and 36 months after the vaccine introduction.

CONCLUSIONS

The study evidenced a significant decrease in the prevalence of rotavirus, mainly in children aged between 0 and 36 months in the 2007-2011 period, as well as a reduction in G1 genotype circulation.

Distribution of rotavirus genotypes after vaccine introduction in the Triângulo Mineiro region of Brazil: 4-Year follow-up study

BACKGROUND

Rotaviruses are the major cause of diarrhea in children for which a monovalent G1P[8] vaccine has been provided free for all Brazilian infants since March 2006.

OBJECTIVES

To investigate prevalence and genotypes of rotavirus strains causing diarrhea in children in Triângulo Mineiro, Minas Gerais, during 2007-2010, and to assess local vaccine impact.

STUDY DESIGN

Fecal specimens were analyzed for rotavirus detection and characterization by PAGE, RT-PCR and PCR-genotyping assays.

RESULTS

Overall, rotavirus was diagnosed in 12.1% (76/630) cases, accounting for 35.8% of the hospitalizations and 6.5% of outpatient attendance due to diarrhea. A trend in rotavirus disease reduction occurred in both cities (71.8% and 83.4% in Uberaba; 95.3% in Uberlândia) up to 2009, but it reversed in 2010 with increased rotavirus cases in Uberlândia. Short pattern G2P[4] strains were detected in all but three (96%) cases of mixed/P[NT] infections with long electropherotypes.

CONCLUSIONS

This 4-year follow-up study showed a reduction in rotavirus-related diarrhea and even skipped a rotavirus season, which is consistent with vaccine mediated protection. The 2007-2010 rotavirus epidemic curve reflected the natural cyclic fluctuation of the single G2P[4] genotype, with sharp reduction of cases in 2008 leading to lack of a rotavirus 2009 season (both cases and hospitalizations) followed by its come back in 2010. Diarrhea cases related to either vaccine serotype/genotype (G1 or P[8]) were not detected. Thus, a new scenario emerged with a single epidemic genotype replacing the cocirculation of great diversity of genotypes, thus far, a hallmark of the epidemiology of rotavirus in Brazil.

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.

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.

One year environmental surveillance of rotavirus specie A (RVA) genotypes in circulation after the introduction of the Rotarix® vaccine in Rio de Janeiro, Brazil

Rotavirus specie A (RVA) infection is the leading cause of severe acute diarrhea among young children worldwide. To reduce this major RVA health impact, the Rotarix® vaccine (GlaxoSmithKline, Rixensart, Belgium) was introduced in the Brazilian Expanded Immunization Program in March 2006 and became available to the entire birth cohort. The aim of this study was to evaluate the spread of RVA in the environment after the introduction of Rotarix® in Brazil. For this purpose, a Wastewater Treatment Plant (WTP) in Rio de Janeiro was monitored for one year to detect, characterize and discriminate RVA genotypes and identify possible circulation of vaccine strains. Using TaqMan® quantitative PCR (qPCR), RVA was detected in 100% (mean viral loads from 2.40×10(5) to 1.16×10(7) genome copies (GC)/L) of sewage influent samples and 71% (mean viral loads from 1.35×10(3) to 1.64×10(5)GC/L) of sewage effluent samples. The most prevalent RVA genotypes were P[4], P[6] and G2, based on VP4 and VP7 classification. Direct nucleotide sequencing (NSP4 fragment) and restriction enzyme digestion (NSP3) analysis did not detect RVA vaccine-like strains from the sewage samples. These data on RVA detection, quantification and molecular characterization highlight the importance of environmental monitoring as a tool to study RVA epidemiology in the surrounding human population and may be useful on ongoing vaccine monitoring programs, since sewage may be a good screening option for a rapid and economical overview of the circulating genotypes.

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.

Full genomic analyses of two human G2P[4] rotavirus strains detected in 2005: identification of a caprine-like VP3 gene

Although G2P[4] rotaviruses are common causes of infantile diarrhoea, to date only the full genomes of the prototype (strain DS-1) and another old strain, TB-Chen, have been analysed. We report here the full genomic analyses of two Bangladeshi G2P[4] strains, MMC6 and MMC88, detected in 2005. Both the strains exhibited a DS-1-like genotype constellation. Excluding the VP4 and VP7 genes, and except for VP3 of MMC88, the MMC strains were genetically more closely related to the contemporary G2P[4] and several non-G2P[4] human strains than the prototype G2P[4] strain. However, by phylogenetic analyses, the VP2, VP3 (except MMC88), NSP1 and NSP3–5 genes of these strains appeared to share a common origin with those of the prototype strain, whilst their VP1, VP6 and NSP2 genes clustered near a caprine strain. The VP3 gene of MMC88 exhibited maximum relatedness to a local caprine strain, representing the first reported human G2P[4] strain with a gene of animal origin.

Effectiveness of the monovalent G1P[8] human rotavirus vaccine against hospitalization for severe G2P[4] rotavirus gastroenteritis in Belém, Brazil

BACKGROUND

Brazil initiated universal immunization of infants with the G1P[8] human rotavirus (RV) vaccine in March 2006. This study evaluated vaccine effectiveness (VE) against severe rotavirus gastroenteritis (RVGE) hospitalizations.

METHODS

Matched case-control study conducted at 4 hospitals in Belém from May 2008 to May 2009. Cases were children hospitalized with RVGE age-eligible to have received 2 doses of the human RV vaccine (≥ 12 weeks of age and born after March 6, 2006). For each case, 1 neighborhood and 1 hospital control without gastroenteritis was selected, matching by birth date (± 8 and ± 6 weeks, respectively). Matched odds ratio of 2-dose RV vaccination in cases versus controls was used to estimate VE (1 - odds ratio × 100%).

RESULTS

Of 538 RVGE cases, 507 hospital controls and 346 neighborhood controls included, 54%, 61%, and 74% had received both RV vaccine doses. VE against RVGE hospitalization was 75.8% (95% confidence interval [CI]: 58.1-86.0) using neighborhood controls and 40.0% (95% CI: 14.2-58.1) using hospital controls. VE in children 3 to 11 months and ≥ 12 months of age was 95.7% (95% CI: 67.8-99.4) and 65.1% (95% CI: 37.2-80.6) using neighborhood controls, and 55.6% (95% CI: 12.3-77.5) and 32.1% (95% CI: -3.7-55.5) using hospital controls. G2P[4] accounted for 82.0% of RVGE hospitalizations. G2P[4]-specific VE was 75.4% (95% CI: 56.7-86.0) using neighborhood controls and 38.9% (95% CI: 11.1-58.0) using hospital controls.

CONCLUSIONS

Although fully heterotypic G2P[4] was the predominant RV strain, good VE was demonstrated. VE was highest in children aged 3 to 11 months. However, protection in children ≥ 12 months of age, important for optimal public health impact, was significantly sustained based on estimates obtained using neighborhood controls.

The detection of enteric viruses in selected urban and rural river water and sewage in Kenya, with special reference to rotaviruses

AIM

To determine the occurrence of eight human enteric viruses in surface water and sewage samples from different geographical areas in Kenya.

METHODS AND RESULTS

Enteric viruses were recovered from the water and sewage sources by glass-wool adsorption elution and/or polyethylene glycol/NaCl precipitation and detected by singleplex real-time and conventional PCR and reverse transcriptase-PCR assays. One or more enteric viruses were detected in nearly all sewage and river water samples except the urban Mbagathi River. The VP7 (G types) and the VP4 (P types) of the rotaviruses (RV) were characterized by multiplex nested PCR methods. The G and P types could be determined in 95·5% of the RV strains, respectively. Mixed G types were detected with G12 and G1 predominating, and unusual G types, G5 and G10, were present. P[4] predominated in the urban Karen sewage samples, while P[8] predominated in the urban and rural streams.

CONCLUSIONS

The high prevalence of RVs in surface water highlights the importance of assessing the water sources used for domestic purposes for viral contamination.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrates the benefit of environmental surveillance as an additional tool to determine the epidemiology of RVs and other enteric viruses circulating in a given community.

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.

Burden of rotavirus gastroenteritis in the Middle Eastern and North African pediatric population

Background

Rotavirus gastroenteritis (RVGE) is the most common cause of severe childhood diarrhea worldwide. Objectives were to estimate the burden of RVGE among children less than five years old in the Middle East (Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, Syria, UAE, Yemen), North Africa (Algeria, Egypt, Libya, Morocco, Tunisia) and Turkey.

Methods

A comprehensive literature search was conducted in major databases on the epidemiology and burden of rotavirus among children less than five years old between 1999 and 2009. Data from each country was extracted and compared.

Results

The search identified 43 studies. RVGE was identified in 16-61% of all cases of acute gastroenteritis, with a peak in the winter. RVGE-related hospitalization rates ranged from 14% to 45%, compared to 14%-28% for non-RVGE. Annually, RVGE caused up to 112 fatalities per 100,000 in certain countries in the region. Hospitalization costs ranged from $1.8 to $4.6 million annually, depending on the country. The most recent literature available showed that G1P[8] was the most prevalent genotype combination in 8 countries (range 23%-56%). G2P[4] was most prevalent in 4 countries (26%-48%). G9P[8] and G4P[8] were also frequently detected.

Conclusions

RVGE is a common disease associated with significant morbidity, mortality, and economic burden. Given the variety and diverse rotavirus types in the region, use of a vaccine with broad and consistent serotype coverage would be important to help decrease the burden of RVGE in the Middle East and North Africa.

Distribution of rotavirus genotypes after introduction of rotavirus vaccines, Rotarix® and RotaTeq®, into the National Immunization Program of Australia

BACKGROUND

Rotavirus vaccines, RotaTeq and Rotarix, were introduced into the Australian National Immunization Program on July 1, 2007. The simultaneous introduction in different Australian states and territories provides a unique opportunity to compare the affect of each vaccine on the types of circulating rotavirus strains. This report describes the rotavirus genotypes responsible for the hospitalization of children during the first 2-year period after vaccine introduction.

METHODS

A total of 764 rotavirus-associated diarrheal cases were collected from children presenting to hospital in 10 Australian centers. Rotavirus genotype was determined using reverse transcription polymerase chain reaction assays.

RESULTS

G1P[8] was the dominant genotype nationally (52%), followed by G2P[4] (19.8%), G9P[8] (12.2%), and G3P[8] (11%). Differences in the prevalence rates of G2P[4] and G3P[8] were seen in the various states. G2P[4] strains were more prevalent in states using Rotarix, whereas G3P[8] strains were more prevalent in states using RotaTeq.

CONCLUSIONS

Differences in rotavirus genotypes were observed across Australia, which suggest that different immune pressures are exerted by the different vaccines, but do not necessarily imply lack of protection by either vaccine. These differences may simply be related to the variation that can occur because of natural annual fluctuation in rotavirus strain prevalence.

Outbreak of acute gastroenteritis caused by adenovirus type 41 in a kindergarten

In response to an alert due to epidemic gastroenteritis in children in a kindergarten, an outbreak investigation was carried out in a Portuguese municipality. The objectives were to establish an aetiological diagnosis, assess vaccine efficacy if possible, and to take corrective measures if necessary. The warden at the kindergarten was interviewed, and we visited the premises. The overall attack rate was 11·4% and most cases were mild. Stool samples from three symptomatic children were collected and screened for the presence of noroviruses, rotaviruses and adenoviruses. High vaccination coverage against rotaviruses was recorded in children aged <2 years. We initially thought that noroviruses and rotaviruses were more likely to have been the aetiological cause of the disease, but the outbreak was caused by infection with adenovirus 41. These viruses should not be overlooked in the laboratory protocol in the study of acute gastroenteritis outbreaks.

Prevention and treatment of viral diarrhea in pediatrics

Diarrhea is the second largest cause of mortality worldwide in children from the perinatal period to the age of 5 years. Rotavirus has been the most commonly identified viral cause of diarrhea in children. Norovirus is now recognized as the second most common viral pathogen. Adenovirus, astrovirus and sapovirus are the other major viral causes of pediatric gastroenteritis. Strategies for prevention include basic hygiene, optimization of nutrition and, ultimately, vaccination. Two new vaccines have recently been licensed for the prevention of rotavirus, the monovalent human rotavirus vaccine (Rotarix) and the pentavalent bovine-human reassortant vaccine (RotaTeq). These vaccines have already dramatically decreased the morbidity associated with rotavirus in countries where they are widely used. Efforts to develop a norovirus vaccine face substantial hurdles. Treatment of the viral pathogens is primarily limited to symptomatic measures.

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.

Rotavirus vaccines for the developing world

PURPOSE OF REVIEW

The authors discuss the most relevant information in the field of rotavirus vaccines published from October 2007 to June 2009; new information on the virus, host response and disease burden that relate to our understanding of vaccine mechanisms and impact are discussed. The review will focus on the role of the vaccines for the developing world but this does not preclude the relevance of these vaccines for children living in the industrialized world.

RECENT FINDINGS

Immune mechanisms involved in rotavirus-associated immunity potentially relevant for vaccine-associated immunity continue to be identified including anti-NSP4 antibodies, cellular and mucosal mechanisms. Rotavirus-associated disease burden is high, causing approximately 40% of diarrhea-associated hospitalizations in children less than 5 years of age worldwide; G12, G8 and P[6] antigenic types emerging in developing countries are increasing in prevalence and may share worldwide circulation with the other five more common serotypes. The two currently available vaccines, based on different immune concepts, (VP7/VP4 homotypic specificity for RotaTeq vs. homotypic and heterotypic specificity for Rotarix) have demonstrated high and sustained efficacy in middle and high-income countries. Recent efficacy and effectiveness studies demonstrate acceptable protection levels in the poorest countries of the world against most antigenic types, leading to universal vaccine recommendation. Postlicensure surveillance has not detected any signal of increased risk for intussusception in children vaccinated with any of the two vaccines.

SUMMARY

Rotavirus vaccines are well tolerated and provide adequate protection against moderate to severe disease in high, middle and low-income regions. Partnerships between governments, industry, and funding agencies will now be urgently needed to promote vaccine use, especially in the less privileged countries of the world.