Rotavirus strain surveillance in Latin America: a review of the last nine years

Low Frequency of Adenovirus, Rotavirus, and Norovirus in Pediatric Diarrheal Samples from Central Iran

Background: Acute viral gastroenteritis is a disorder that affects children globally but mostly in developing countries. Adenoviruses, rotaviruses, and noroviruses are the leading viral causes of childhood gastroenteritis. Objectives: This study is the first to investigate the frequency of these viruses in diarrheal samples from pediatric patients living in central Iran. Methods: A total of 173 samples of pediatric diarrhea, from May 2015 to May 2016, were included in this descriptive cross-sectional study. The samples were analyzed using in-house developed PCR and reverse transcription (RT)-PCR methods to investigate the frequency of adenoviruses, rotaviruses, and noroviruses. Results: Out of 173 samples of pediatric diarrhea, eight were shown to contain enteric viruses (4.6%): (1) four with adenoviruses (2.3%); (2) three with rotaviruses (1.7%); and (3) one with a genogroup II norovirus (0.6%). Most of the positive samples were obtained from children under the age of seven. The most common additional clinical symptoms in pediatric patients with viral agents were fever, vomiting, and abdominal pain. Conclusions: In central Iran, adenoviruses and rotaviruses were rarely found as agents responsible for gastroenteritis. Although viral gastroenteritis in this area had less frequency than bacterial gastroenteritis, we need to monitor all enteropathogenic agents for longer periods to understand better real endemicity and the possibility of unexpected viral enteritis outbreaks.

Diversity of Rotavirus Strains in Children; Results From a Community-Based Study in Nepal

Objective: The objectives of this study were to describe the incidence and genetic diversity of Rotavirus (RV) infection among children up to 3 years of age in a community in Nepal.

Methods: We investigated community-acquired cases of asymptomatic and symptomatic RV infections in children from birth to 36 months of age in a community-based birth cohort in Bhaktapur, Nepal. Monthly surveillance and diarrheal stool samples were collected from 240 children enrolled at birth, of which 238 completed the 3 years of follow-up. Samples were screened for rotavirus by Enzyme Immuno Assay (EIA). All RV screened positives were further genotyped by reverse transcription-polymerase chain reaction for the capsid genes VP7 and VP4.

Results: In total, 5,224 stool samples were collected from 238 children, followed from birth to 36 months of age. Diarrhea occurred in 92.4% (230/238) of all children in the cohort. During the 3 years study period, RV was more frequently seen in children with symptoms (7.6%) than in non-symptomatic children (0.8%). The highest RV detection rate was found in younger children between 3 and 21 months of age. Although rotavirus is known as winter diarrhea, it was detected throughout the year except in August. The highest positivity rate was observed in the months between December and March, with a peak in January. Four common G types were seen: G2 (30%), G1 (29%), G12 (19%), and G9 (16%). The most predominant genotypes seen were G2P[4] (30%), followed by G1P[8] (27.0%), G12P[6] (14.0%), G9P[8] (10%), and remaining were mixed, partial, and untyped.

Conclusion: Our study confirms that rotavirus is a common cause of gastroenteritis in young children in the community. The prevalence and pathogenicity of rotavirus infection differed by age. There was substantial variability in circulating strains in the community samples compared to samples collected from hospitals. This shows the importance of including community-based surveillance systems to monitor the diversity of circulating rotavirus strains in Nepal.

Dynamics of G2P[4] strain evolution and rotavirus vaccination: A review of evidence for Rotarix

Rotavirus (RV) gastroenteritis is a vaccine-preventable disease that creates high medical and economic burden in both developed and developing countries. Worldwide, more than 100 countries have introduced RV vaccines in their national immunization programs, and the remarkable impact of reducing the burden of severe childhood gastroenteritis has been unequivocally demonstrated. Currently, 2 oral vaccines (Rotarix, GSK and RotaTeq, Merck) are widely utilized. Recent temporary increases in the relative prevalence of G2P[4] RV strains have been observed in countries implementing RV vaccination. This comprehensive literature review aims to provide an insight on RV genotype evolution in the context of mass vaccination with Rotarix, particularly in the case of G2P[4]. In the post-vaccine era, strain surveillance data indicated temporal and spatial changes in countries both with and without RV vaccination programs. Annual fluctuations in G2P[4] prevalence seem to occur naturally, with no substantial differences between countries using Rotarix, RotaTeq or mixed vaccination programs. Moreover, Rotarix has been shown to be efficacious and effective against gastroenteritis caused by non-vaccine strains, including G2P[4]. These data indicate that shifts in RV genotype distribution are likely to constitute an inherent process of virus evolution to infect the human gut. Following RV vaccine introduction, incidences of RV gastroenteritis declined dramatically and mass vaccination will likely maintain this status, despite possible fluctuations in the relative distribution of genotypes. There is no conclusive evidence of unusual burst of new or vaccine-escape strains since global RV vaccines use. The emergence of strains with a potential to increase the current burden of RV disease should be continuously monitored and can only be established by exhaustive characterization of strains, including whole genomic sequencing. Given the natural fluctuations in RV strains over time, caution is advised when interpreting temporal changes in RV strain dynamics, as they could mistakenly be attributed to vaccination.

Characterisation of a rare, reassortant human G10P[14] rotavirus strain detected in Honduras

BACKGROUND

Although first detected in animals, the rare rotavirus strain G10P[14] has been sporadically detected in humans in Slovenia, Thailand, United Kingdom and Australia among other countries. Earlier studies suggest that the strains found in humans resulted from interspecies transmission and reassortment between human and bovine rotavirus strains.

OBJECTIVES

In this study, a G10P[14] rotavirus genotype detected in a human stool sample in Honduras during the 2010-2011 rotavirus season, from an unvaccinated 30-month old boy who reported at the hospital with severe diarrhea and vomiting, was characterised to determine the possible evolutionary origin of the rare strain.

METHODS

For the sample detected as G10P[14], 10% suspension was prepared and used for RNA extraction and sequence independent amplification. The amplicons were sequenced by next-generation sequencing using the Illumina MiSeq 150 paired end method. The sequence reads were analysed using CLC Genomics Workbench 6.0 and phylogenetic trees were constructed using PhyML version 3.0.

FINDINGS

The next generation sequencing and phylogenetic analyses of the 11-segmented genome of the G10P[14] strain allowed classification as G10-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3. Six of the genes (VP1, VP2, VP3, VP6, NSP2 and NSP4) were DS-1-like. NSP1 and NSP5 were AU-1-like and NSP3 was T6, which suggests that multiple reassortment events occurred in the evolution of the strain. The phylogenetic analyses and genetic distance calculations showed that the VP7, VP4, VP6, VP1, VP3, NSP1, NSP3 and NSP4 genes clustered predominantly with bovine strains. NSP2 and VP2 genes were most closely related to simian and human strains, respectively, and NSP5 was most closely related to a rhesus strain.

MAIN CONCLUSIONS

The genetic characterisation of the G10P[14] strain from Honduras suggests that its genome resulted from multiple reassortment events which were possibly mediated through interspecies transmissions.

Epidemiology of Rotavirus-Norovirus Co-Infection and Determination of Norovirus Genogrouping among Children with Acute Gastroenteritis in Tehran, Iran

Background:

Enteric viruses, particularly human rotavirus and norovirus, have been shown to replace bacteria and parasites, as the most common pathogens responsible for acute diarrhea. However, there are still few epidemiological data on the simultaneous occurrence of these viruses in Iran. In this regard, the aim of this study was to assess the useful epidemiological data on the gastroenteritis associated with rotavirus-norovirus mixed infection and to examine the prevalence of norovirus genogrouping among children aged less than five years old in Iran.

Methods:

A total of 170 stool samples were collected from children under five years of age with the clinical signs and symptoms of acute gastroenteritis, from May 2013 to May 2014. For the detection of both rotavirus and norovirus, total RNA was extracted from all samples, followed by reverse transcription polymerase chain reaction (RT-PCR). For both detected rotaviruses and noroviruses, genogrouping was performed.

Results:

Of 170 samples, 49 (28.8%) and 15 (8.8%) samples were found to be positive for rotavirus and norovirus infections by RT-PCR. Interestingly, 6 (3.5%) patients were positive for both infections. Among the 15 norovirus-positive patients, 13 (86.6%) and 2 (13.3%) belonged to genogroups GII and GI.

Conclusion:

The norovirus genogroup GII and rotavirus lead to the serious infections in children with acute gastroenteritis. However, more well-designed studies are needed to further elucidate the role of other enteric viruses in acute gastroenteritis

Detection of group A rotavirus strains circulating among children with acute diarrhea in Indonesia

Rotavirus is the major cause of severe diarrhea in children under 5 years old in developed and developing countries. Since improvements in sanitation and hygiene have limited impact on reducing the incidence of rotavirus diarrhea, implementation of a vaccine will be a better solution. We conducted an observational study to determine the disease burden and to identify the genotype of circulating rotavirus in Indonesia. Hospitalized children due to acute diarrhea were enrolled from four teaching hospitals in Indonesia. Stool samples were collected based on WHO protocol and were tested for the presence of group A rotavirus using enzyme immunoassay. Then, rotavirus positive samples were genotyped using RT-PCR. Fisher’s Exact tests, Chi square tests and logistic regression were performed to determine differences across hospital and year in rotavirus prevalence and genotype distribution. There were 4235 samples from hospitalized children with diarrhea during 2006, 2009 and 2010. Among them, the rotavirus positive were 2220 samples (52.42 %) and incidence rates varied between hospitals. The G1P[8], G1P[6], and G2P[4] were recognized as the dominant genotypes circulating strains in Indonesia and the proportion of predominant strains changed by year. Our study showed the high incidence of rotavirus infection in Indonesia with G1P[8], G1P[6], and G2P[4] as the dominant strains circulating in Indonesia. These results reinforce the need for a continuing surveillance of rotavirus strain in Indonesia.

Burden of Norovirus and Rotavirus in Children After Rotavirus Vaccine Introduction, Cochabamba, Bolivia

The effectiveness of rotavirus vaccine in the field may set the stage for a changing landscape of diarrheal illness affecting children worldwide. Norovirus and rotavirus are the two major viral enteropathogens of childhood. This study describes the prevalence of norovirus and rotavirus 2 years after widespread rotavirus vaccination in Cochabamba, Bolivia. Stool samples from hospitalized children with acute gastroenteritis (AGE) and outpatients aged 5-24 months without AGE were recruited from an urban hospital serving Bolivia's third largest city. Both viruses were genotyped, and norovirus GII.4 was further sequenced. Norovirus was found much more frequently than rotavirus. Norovirus was detected in 69/201 (34.3%) of specimens from children with AGE and 13/71 (18.3%) of those without diarrhea. Rotavirus was detected in 38/201 (18.9%) of diarrheal specimens and 3/71 (4.2%) of non-diarrheal specimens. Norovirus GII was identified in 97.8% of norovirus-positive samples; GII.4 was the most common genotype (71.4% of typed specimens). Rotavirus G3P[8] was the most prevalent rotavirus genotype (44.0% of typed specimens) and G2P[4] was second most prevalent (16.0% of typed specimens). This community is likely part of a trend toward norovirus predominance over rotavirus in children after widespread vaccination against rotavirus.

Impact of vaccination on the molecular epidemiology and evolution of group A rotaviruses in Latin America and factors affecting vaccine efficacy

Despite high rotavirus (RV) vaccine coverage (∼83%) and good effectiveness (∼77%) against RV-diarrhea hospitalization, RV is still contributing to the burden of diarrhea that persists in hospital settings in several Latin American countries, where RV vaccination is being implemented. Due to the extensive genomic and antigenic diversity, among co-circulating human RV, a major concern has been that the introduction of RV vaccination could exert selection pressure leading to higher prevalence of strains not included in the vaccines and/or emergence of new strains, thus, reducing the efficacy of vaccination. Here we review the molecular epidemiology of RV in Latin America and explore issues of RV evolution and selection in light of vaccination. We further explore etiologies behind the large burden of diarrhea remaining after vaccination in some countries and discuss plausible reasons for vaccine failures.

Rotavirus diversity among diarrheal children in Delhi, India during 2007-2012

Rotavirus is the leading cause of severe gastroenteritis in young children worldwide and is responsible for around 100,000 deaths in India annually. Vaccination against rotavirus (RV) is a high priority: 'ROTAVAC' an indigenous vaccine will soon be licensed in India. Surveillance to determine the impact of vaccines on emerging RV strains is required. In this study we compared the pattern of RV strains circulating in Delhi over a 5 year period with the strains over the past 12 years. The most commonly detected G genotypes were G1 (22.4%), G2 (17.2%), and G9 (25.2%) with P[4] (25.5%), P[6] (20%) and P[8] (16.9%) specificity. G12 genotype was found to be the fourth common G-type with 14.8% prevalence. Among the G-P combinations; G1P[8], G2P[4], G9P[8] and G12P[6] were detected at 7.2%, 7.2%, 5.2% and 10%, respectively. Of note, G9P[4] and G2P[6] that were rarely detected during 2000-2007 in Delhi, were observed quite frequently with prevalence of 6.5% and 3.4%, respectively. In total, 16 different G-P combinations were detected in the present study demonstrating the rich diversity of rotavirus strains in Delhi. Our data from the 12 year period indicate wide circulation of G1 and G9 genotypes in combination with P[8], G2 with P[4] and G12 with P[6] with high frequency of RV strains having rare G-P combinations in Delhi. Since the indigenous vaccine 'ROTAVAC' has a monovalent formulation, the impact of vaccines on strains and the effect of strain diversity on the efficacy of the vaccine should be monitored.

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).

Genetic diversity of G3 rotavirus strains circulating in Argentina during 1998-2012 assessed by full genome analyses

Seasonal shifts in the predominant strains and the periodic emergence of new strains are epidemiological features of human rotaviruses. After the sporadic detection in two samples in 1998, G3P[8] strains reemerged as the predominant rotavirus during 2008-2009 in Argentina. Notably, in 2011 6.3% (37/587) of samples presented the G3P[6] genotypes, which coincided with the recent detection of G3P[6] and G2P[6] strains in South America and Europe. Analyses of the 11 gene segments of four G3P[8] and two G3P[6] strains revealed that G3P[8] strains detected a decade apart (1998 and 2009) presented minor differences, while the G3P[6] strains presented a complete different genomic constellation albeit showing a similar VP7 gene. This study provides insights in the dynamics and evolution of one of the genotypes with the wider range of hosts and inter-species transmission potential.

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.

Epidemiology and clinical features of rotavirus and norovirus infection among children in Ji'nan, China

Background

Acute gastroenteritis caused by bacteria, virus and parasite is an important cause of childhood morbidity and mortality in developing countries. Rotavirus and norovirus have been recognized as the most common pathogens causing acute gastroenteritis among children. However, there is still no valuable data about infections of rotavirus and norovirus in children in Ji’nan, an eastern city in China. The aims of the present study are to determine the incidence of rotavirus and norovirus associated acute gastroenteritis in Ji’nan among children, to characterize rotavirus and norovirus strains circulating during this period; and to provide useful epidemiological and clinical data.

Methods

Fecal specimens and clinical data were collected from 767 children (502 outpatients and 265 inpatients) under 5 years of age with acute diarrhea at Shandong University Qilu Hospital and Qilu children’s Hospital in Ji’nan, China between February 2011 and January 2012. Virus RNA was extracted, amplified, electrophoresed, sequenced and phylogenetically analyzed to determine the prevalent genotypes. Chi-square and U test were used to compare characteristics of clinical manifestation in each group.

Results

Of the 767 specimens 263 (34.3%) were positive for rotavirus and 80 (10.4%) were positive for norovirus. Among 263 rotavirus positive cases, G3 (40.7%) was the most prevalent serotype, P[8] (46.8%) was the dominant genotype and G3P[8] (31.9%) was the most common combination. All of the norovirus strains belonged to GII genogroup including GII.3, GII.4 and GII.6, of which GII.4 (61.2%) was the predominant genotype. Phylogenetic analysis of the GII.4 sequences showed that 18 GII.4 strains belonged to GII.4 2004–2006 cluster and 31 GII.4 strains were divided into GII.4 2006b cluster. A peak number of rotavirus infections was observed during the cold season from November to next January. Higher rates of norovirus infections were detected from September to November. Most patients with rotavirus and norovirus associated diarrhea experienced vomiting (88.2% and 67.5%, respectively) and fever (79.1% and 46.3%, respectively).

Conclusions

The present study showed that rotavirus and norovirus were still the important causative agents of pediatric diarrhea in Ji’nan during this period.

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.

[Comparison of clinical characteristics of patients with rotavirus gastroenteritis relative to the infecting rotavirus g-p genotype.]

BACKGROUND

Group A rotavirus is a major cause of severe diarrhea in children throughout the world. For the proper management of rotavirus infections, it will be helpful to know their clinical characteristics according to the G and P genotypes of the infecting virus.

METHODS

The diarrheal stool specimens from patients hospitalized in Chosun University Hospital during 2002-2003 were tested for rotavirus by Dipstick 'Eiken' Rota kit. Rotavirus antigen-positive stool specimens were analyzed for group A rotavirus by RT-PCR, and the group A-positive PCR products were genotyped for P and G types by PCR.

RESULTS

Among the 119 specimens analyzed for genotypes, the predominant strain was genotype G4P[6] (51.3%), followed by G2P[4] (19.3%), G1P[8] (7.6%), G3P[8] (5.0%), and G9P[8] (4.2%). To examine the characteristics of each rotavirus genotype, a clinico-epidemiological study was performed for 100 patients whose medical records were available. The frequencies of diarrhea, vomiting, dehydration, and fever; the rates of nosocomial infection and transfer from other hospitals; and the mean severity scores were significantly different among the patients infected with different types of rotavirus. Especially, patients with G4P[6] type were more likely than those infected with other genotypes to show the following distinct features: Most patients showed milder symptoms and were neonates transferred from other obstetric hospitals and 68.4% of the cases were nosocomial infection. G4P[6] strains were isolated almost all along the year. The mean severity scores of patients infected by G4P[6], G2P[4], G1P[8], G3P[8], and G9P[8] strains were 6.8, 9.5, 8.0, 9.0, and 10.8, respectively.

CONCLUSIONS

Many features of rotavirus infections including the epidemic period, rate of nosocomial infection, age and severity of symptoms were different according to the genotypes of the infecting virus.

Human rotavirus vaccine is highly efficacious when coadministered with routine expanded program of immunization vaccines including oral poliovirus vaccine in Latin America

BACKGROUND

The efficacy of a rotavirus vaccine against severe rotavirus gastroenteritis when coadministered with routine Expanded Program on Immunization (EPI) vaccines including oral polio vaccine (OPV) was evaluated in this study.

METHODS

Double-blind, randomized (2:1), placebo-controlled study conducted across 6 Latin American countries. Healthy infants (N = 6568) 6 to 12 weeks of age received 2 doses of RIX4414 vaccine or placebo following a 0, 1- to 2-month schedule. Routine vaccines including OPV were coadministered according to local EPI schedule. Vaccine efficacy (VE) against severe rotavirus gastroenteritis caused by circulating wild-type rotavirus from 2 weeks post-Dose 2 until 1 year of age was calculated with 95% confidence interval [CI]. Safety was assessed during the entire study period. Immunogenicity of RIX4414 and OPV was also assessed.

RESULTS

During the efficacy follow-up period (mean duration = 7.4 months), 7 and 19 cases of severe rotavirus gastroenteritis were reported in the vaccine and placebo groups, respectively, with a VE of 81.6% (95% CI: 54.4-93.5). VE against severe rotavirus gastroenteritis caused by G1 type was 100% (95% CI: <0-100) and 80.6% (95% CI: 51.4-93.2) against the pooled non-G1 rotavirus types, respectively. There was no difference (P = 0.514) in the incidence of serious adverse events reported in the 2 groups. Antirotavirus IgA seropositivity rate at 1 to 2 months post-Dose 2 was 61.4% (95% CI: 53.7-68.6) in the RIX4414 group; similar seroprotection rates (≥96.0%) against the 3 antipoliovirus types was observed 1 month post-Dose 3 of OPV in both groups.

CONCLUSION

RIX4414 was highly efficacious against severe rotavirus gastroenteritis caused by the circulating wild-type rotavirus (G1 and non-G1) when coadministered with routine EPI vaccines including OPV.

Burden and typing of rotavirus group A in Latin America and the Caribbean: systematic review and meta-analysis

The efficacy of licensed rotavirus vaccines has only been shown against certain rotavirus group A (RV-A) types. It is critical to understand the burden of rotavirus gastroenteritis (RVGE) and its prevalent types to assess the potential impact of these vaccines in Latin America and the Caribbean (LA&C). We performed a systematic review and meta-analyses of all the available evidence reported from 1990 to 2009 on the burden of rotavirus disease and strains circulating in LA&C. Eligible studies--185 country-level reports, 174 951 faecal samples--were selected from MEDLINE, Cochrane Library, EMBASE, LILACS, regional Ministries of Health, PAHO, regional proceedings, doctoral theses, reference lists of included studies and consulting experts. Arc-sine transformations and DerSimonian-Laird random-effects model were used for meta-analyses. The proportion of gastroenteritis cases due to rotavirus was 24.3% (95%CI 22.3-26.4) and the incidence of RVGE was 170 per 1000 children-years (95%CI 130-210). We estimated a global annual mortality for 22 countries of 88.2 (95%CI 79.3-97.1) deaths per 100 000 under 5 years (47 000 deaths).The most common G type detected was G1 (34.2%), followed by G9 (14.6%), and G2 (14.4%). The most common P types detected were P[8] (56.2%), P[4] (22.1%) and P[1] 5.4%, and the most prevalent P-G type associations were P[8]G1 17.9%, P[4]G2 9.1% and P[8]G9 8.8%. In the last 10 years, G9 circulation increased remarkably and G5 almost disappeared. More recently, G12 appeared and P[4]G2 re-emerged. To our knowledge, this is the first meta-analysis of rotavirus infection and burden of disease in LA&C.

Changes in childhood diarrhea incidence in nicaragua following 3 years of universal infant rotavirus immunization

BACKGROUND

Although the pentavalent rotavirus vaccine was highly efficacious against rotavirus diarrhea in clinical trials, the effectiveness of vaccine under field conditions in the developing world is unclear. In October 2006, Nicaragua became the first developing nation to implement universal infant immunization with the pentavalent rotavirus vaccine. To assess the effect of the immunization program, we examined the incidence of diarrhea episodes between 2003 and 2009 among children in the state of León, Nicaragua.

METHODS

We extracted data on diarrhea episodes from health ministry records. We used scaled Poisson regression models to estimate diarrhea incidence rate ratios for the period following the program's implementation to the period before implementation.

RESULTS

Following implementation of the immunization program, diarrhea episodes among infants were reduced (incidence rate ratios: 0.85, 95% confidence interval: 0.71-1.02) during the rotavirus season, but appear to have increased during other months.

CONCLUSIONS

Although the immunization program appears effective in reducing diarrhea episodes during the rotavirus season, a large burden of diarrhea still persists during the remainder of the year.

Laboratory-based rotavirus surveillance during the introduction of a vaccination program, Brazil, 2005-2009

BACKGROUND

: Brazil introduced universal antirotavirus vaccination in March 2006. This article reports the results of rotavirus A (RV-A) surveillance from January 2005 to December 2009.

METHODS

: A total of 6109 fecal samples were collected in 18 Brazilian states. RV-A was detected by enzyme immunoassay and/or polyacrylamide gel electrophoresis, and genotyped through seminested reverse transcription-polymerase chain reaction.

RESULTS

: RV-A was detected in 20.3% (n = 1242) of the samples. Among children less than 2 years old, regardless the antirotavirus vaccination status, the rates of RV-A detection were 33.8% in 2005, 23.7% in 2006, 16.8% in 2007, 22.9% in 2008, and 18.3% in 2009 (P < 0.001; χ test for linear trend). Among RV-A-positive samples, genotype G1P[8] or G1P[not typed(NT)] was detected in 14% in 2005, 12.3% in 2006, 9.5% in 2007, 0.7% in 2008, and 20.4% in 2009; G2P[4]/G2P[NT] was characterized in 9% in 2005, 49% in 2006, 66% in 2007, 85% in 2008, and 37.5% in 2009; G3P[8]/G3P[NT] was observed in 8.7% in 2005, 3.5% in 2006, and 5.7% in 2009; G9P[8]/G9P[NT] was observed in 52% in 2005, 22% in 2006, 12.3% in 2007, 3.2% in 2008, and 3.4% in 2009.

CONCLUSIONS

: Our data demonstrate the reemergence of RV-A genotype G2P[4] in Brazil from 2005 to 2008, and that the rate of G2P[4] detection decreased in 2009, probably reflecting natural oscillations of RV-A genotypes.

Molecular epidemiology of group A rotavirus in Buenos Aires, Argentina 2004-2007: reemergence of G2P[4] and emergence of G9P[8] strains

Detection and characterization of group A rotavirus in Buenos Aires, Argentina, was conducted on 710 fecal samples from children 0-15 years old collected between 2004 and 2007. Rotavirus was detected in 140 (19.7%) samples with G9P[8] (30.0%) and G2P[4] (21.4%) as the most common genotypes. Mixed (G and/or P) infections accounted for 17.9% of the samples and the emerging G12 strain was detected during 2004 (3.5%) and 2007 (2.5%). Genotype G2 was the most prevalent during 2004 (43.9%) and 2007 (57.5%) and G9 during 2005 (58.0%) and 2006 (61.5%). Analysis of genotype prevalences from studies performed since 1996 in the same area showed striking natural fluctuations in G and P genotype frequencies. In particular, G2P[4] strains disappeared after 1999 and reemerged in 2004 to become the predominant strain by 2007 with a concomitant major decrease in G1P[8] prevalence. The VP7 genes from Argentinian G9 and G2 strains were sequenced and phylogenetic analysis was conducted in order to compare with sequences from strains isolated in regional countries reported previously. Several changes in the deduced amino acid sequence in antigenic regions of the VP7 protein from Argentinian and Brazilian strains were identified compared to vaccine strains. Overall, this study revealed relationships in the circulation of rotavirus strains in South American countries and major replacements in dominant genotypes, including the virtual disappearance of G1P[8] strains in a non-vaccinated population. High numbers of mixed infections speeding up evolution, circulation of rare serotypes, and antigenic drift could, eventually, become challenges for new vaccines.

Rotavirus genotype G4P[8] and enteric adenovirus in HIV-positive patients with and without diarrhoea in São Paulo State, Brazil

The present study was carried out in order to identify rotavirus and enteric adenovirus in HIV-positive patients with and without diarrhoea, collected in a pre- and early highly active antiretroviral therapy era. Rotavirus was detected in 2.5% (3/118) and adenovirus in 14.4% (17/118) of the samples from patients without diarrhoea. In the patients with diarrhoea, rotavirus was identified in 1.5% (2/133) and adenovirus in 7.5% (10/133). These findings suggest no increased frequency of virus excretion in HIV-infected patients with diarrhoea. The genotype G4P[8] was characterized in all positive rotavirus samples, and this is the first report of rotavirus molecular characterization in HIV-positive patients in Brazil.

Licensed Vaccines for Rotavirus Prevention in the US: A Review

Objective:

To review the pharmacology, efficacy, safety, and tolerability of RotaTeq and RotaRix, 2 rotavirus vaccines.

Data Sources:

English-language articles were obtained via MEDLINE (1966-August 2009) and EMBASE (1980-August 2009) searches using the key words rotavirus vaccine, epidemiology, diarrhea, intussusception, RotaShield, RotaTeq, and RotaRix. Bibliographies of selected articles were used to identify additional sources.

Study Selection and Data Extraction:

Available published articles reporting the results of human studies of rotavirus vaccines were reviewed for inclusion in this article. Additional information regarding clinical trials and adverse events was obtained from the manufacturer's prescribing information for each vaccine.

Data Synthesis:

RotaTeq is a live, attenuated human-bovine pentavalent vaccine, and RotaRix is a live, attenuated human vaccine. Both vaccines are approved for the prevention of rotavirus infection and recommended for routine immunization in healthy infants aged 14 weeks to 8 months. The vaccines differ in virologic characteristics, but clinical trials indicate similar efficacy and safety. Each vaccine is more than 70% effective in preventing any severity of rotavirus gastroenteritis and more than 98% effective in preventing severe disease through one full season of rotavirus exposure postvaccination. Efficacy begins to wane during the second season of rotavirus exposure. Post hoc analyses of clinical trials indicated an 85–100% reduction in hospitalizations and emergency department visits following vaccination. Both vaccines have been well tolerated. Fever, vomiting, and diarrhea are the most reported adverse events. Intussusception and Kawasaki syndrome have been reported, but occurrence of these events has not been shown to be significant in comparison with the background rate for each adverse event.

Conclusions:

RotaTeq and RotaRix are effective for the prevention of rotavirus infection in the US, Europe, and Latin America. Additional studies are needed to assess their duration of protection, worldwide efficacy, effect on the reduction of healthcare resource utilization, and adverse event monitoring.

Predominance and circulation of enteric viruses in the region of Greater Cairo, Egypt

The circulation of enteric viruses among the population of Cairo, Egypt, between March 2006 and February 2007 was studied. At least one virus was detected in 50% of fecal samples, 57.4% of which were positive for rotavirus, 26% for norovirus, 10.4% for adenovirus, and 1.7% for astrovirus. Over 10% of infections were mixed infections. Rotavirus typing showed that G1P[8] and G2P[4] were predominant but that the unusual G12P[4] and G12P[6] reassortants were also present. Among the noroviruses, half belonged to the predominant GGII.4 cluster. The phylogenetic analysis of the capsid gene suggested that GGII.4 strains from Cairo were similar to those circulating elsewhere. It also showed the emergence of new GGII.4 variants that were not associated with any previously known GGII.4 isolate. Further studies are required to assess the disease burden of enteric viruses in Egypt and the impact of atypical strains.

Molecular epidemic features and variation of rotavirus among children with diarrhea in Lanzhou, China, 2001-2006

BACKGROUND

Human rotavirus (HRV) is the most common pathogen causing severe diarrhea among infants and young children worldwide. This study aims to understand rotavirus epidemiology and its variation in the period of 2001-2006 in Lanzhou, Gansu Province, China, and to provide an epidemiological basis for the development of rotavirus vaccine.

METHODS

A total of 1019 stool specimens were collected from patients with acute diarrhea admitted to the First Hospital of Lanzhou University from 2001 to 2006, who were younger than 5 years old. Dako IDEIATM kits were used for detection of rotavirus, and RT-PCR was performed for determination of G serotype and P genotype of the rotavirus.

RESULTS

Rotavirus was present in 51.6% (526) of the 1019 specimens. G serotype identified G3 at 40.9%, G2 14.6%, G1 22.2% and G9 1.9%. Mixed-G infection was observed in 4.4% and non-typeable infection 16.0%. P genotype was observed in 372 samples, of which P[8] accounted for 186 cases (50.0%), P[4] 72 cases (19.4%), mixed-P infection 2 cases (0.5%), and non-typeable cases 112 (30.1%). G3 was the most prevalent G serotype found in this study from 2001 to 2004, G2 was the most prevalent G serotype (34.4%) from 2004 to 2005, and G1 (61.5%) was the most prevalent strain from 2005 to 2006. G9 was detected in 10 cases (1.9%) and G4 was not detected during this 5-year period. P[8] was the most prevalent P genotype found over the 5 consecutive years of this study, although there was a significant transition of P genotype from 2004 to 2005 with P[4] (45%) identified as the predominant P genotype, followed by P[8] (22.1%). The predominant G-P combination was P[8]G1 (33.6%), followed by P[8]G3 (32.1%) and P[4]G2 (17.2%). Rotavirus diarrhea admissions peaked between October and December. Continuous surveillance showed that the incidence rate of rotavirus was the highest in infants aged 6-23 months, averaging 11.0-11.9 months.

CONCLUSIONS

Five years of continuous surveillance showed that rotavirus remains the most significant viral agent causing diarrhea hospitalization among children under 5 years old in Lanzhou, China although the predominant strain of rotavirus varies between years. Mixed-G serotype infection also appears to occur at a relatively high rate in Lanzhou.

Efficacy and safety of an oral live attenuated human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in Latin American infants: a randomised, double-blind, placebo-controlled phase III study

BACKGROUND

Peak incidence of rotavirus gastroenteritis is seen in infants between 6 and 24 months of age. We therefore aimed to assess the 2-year efficacy and safety of an oral live attenuated human rotavirus vaccine for prevention of severe gastroenteritis in infants.

METHODS

15 183 healthy infants aged 6-13 weeks from ten Latin American countries randomly assigned in a 1 to 1 ratio to receive two oral doses of RIX4414 or placebo at about 2 and 4 months of age in a double-blind, placebo-controlled phase III study were followed up until about 2 years of age. Primary endpoint was vaccine efficacy from 2 weeks after dose two until 1 year of age. Treatment allocation was concealed from investigators and parents of participating infants. Efficacy follow-up for gastroenteritis episodes was undertaken from 2 weeks after dose two until about 2 years of age. Analysis was according to protocol. This study is registered with ClinicalTrials.gov, number NCT00140673 (eTrack444563-023).

FINDINGS

897 infants were excluded from the according-to-protocol analysis. Fewer cases (p<0.0001) of severe rotavirus gastroenteritis were recorded for the combined 2-year period in the RIX4414 group (32 [0.4%] of 7205; 95% CI 0.3-0.6) than in the placebo group (161 [2.3%] of 7081; 1.9-2.6), resulting in a vaccine efficacy of 80.5% (71.3-87.1) to 82.1% (64.6-91.9) against wild-type G1, 77.5% (64.7-86.2) against pooled non-G1 strains, and 80.5% (67.9-88.8) against pooled non-G1 P[8] strains. Vaccine efficacy for hospital admission for rotavirus gastroenteritis was 83.0% (73.1-89.7) and for admission for diarrhoea of any cause was 39.3% (29.1-48.1). No cases of intussusception were reported during the second year of follow-up.

INTERPRETATION

Two doses of RIX4414 were effective against severe rotavirus gastroenteritis during the first 2 years of life in a Latin American setting. Inclusion of RIX4414 in routine paediatric immunisations should reduce the burden of rotavirus gastroenteritis worldwide.

Evaluation of Circulating Intestinally Committed Memory B Cells in Children Vaccinated with Attenuated Human Rotavirus Vaccine

In a double blind trial, 319 fully immunized children received two doses of either placebo or 10(6.7) focus-forming units of the attenuated RIX4414 human rotavirus (RV) vaccine ("all-in-one" formulation). Plasma RV-specific IgA (RV IgA), stool RV IgA, and circulating total and RV memory B cells (CD19+ IgD+/- CD27+) with an intestinal homing phenotype (alpha4beta7+ CCR9+/-) were measured, after the first and second doses, as potential correlates of protection. After the first and/or second dose, 54% of vaccinees and 13% of placebo recipients had plasma RV IgA. Before vaccination, most (95%) of the children (of both study groups) were breast-fed and had stool RV IgA (68.64%). Coproconversion (4-fold increase) after the first and/or second dose was observed in 32.7% of vaccinees and 17.4% of placebo recipients. No significant difference was seen when comparing the frequencies of any subset of memory B cells between vaccinees and placebo recipients. Statistically significant weak correlations were found between plasma RV IgA titers and coproconversion, and several subsets of memory B cells. The vaccine provided 74.8% protection (95% confidence interval, 30.93-92.62) against any RV gastroenteritis and 100% protection (95% confidence interval, 14.53-100) against severe RV gastroenteritis. When vaccinees and placebo recipients were considered together, a correlation was found between protection from disease and plasma RV IgA measured after dose 2 and RV memory (IgD- CD27+ alpha4beta7+ CCR9+) circulating B cells measured after dose 1. However, the correlation coefficients for both tests were low (<0.2), suggesting that other factors are important in explaining protection from disease.

Symptomatic and subclinical infection with rotavirus P[8]G9, rural Ecuador

During the past decade, rotavirus genotype G9 has spread throughout the world, adding to and sometimes supplanting the common genotypes G1-G4. We report evidence of this spread in a population sample within rural Ecuador. A total of 1,656 stool samples were collected from both patients with diarrhea and from asymptomatic residents in 22 remote communities in northwestern Ecuador from August 2003 through February 2006. Rotavirus was detected in 23.4% of case-patients and 3.2% of controls. From these 136 rotavirus-positive samples, a subset of 47 were genotyped; 72% were of genotype G9, and 62% were genotype P[8]G9. As a comparison, 29 rotavirus-positive stool samples were collected from a hospital in Quito during March 2006 and genotyped; 86% were of genotype P[8]G9. Few countries have reported P[8]G9 rotavirus detection rates as high as those of the current study. This growing prevalence may require changes to current vaccination programs to include coverage for this genotype.

Anticipating rotavirus vaccines in Brazil: Detection and molecular characterization of emerging rotavirus serotypes G8 and G9 among children with diarrhoea in Recife, Brazil

In 2006, Brazil will initiate universal immunization of its 4-million infants with a live attenuated serotype G1P[8] human rotavirus vaccine. In anticipation of the national immunization program, this study was undertaken to characterize rotavirus strains circulating among children in Recife, one of the largest cities in the northeast region of Brazil. Group A rotaviruses were detected in 102 (35%) of 290 faecal specimens collected from children under 5 years of age who presented with acute diarrhoea during a 1-year period between May 2004 and April 2005. In addition to the globally common G1P[8] serotype that accounted for 49% of strains, emerging rotavirus serotypes G8P[6] and G9P[8] represented 2% and 29% of strains, respectively. Following cell culture adaptation, RNA-RNA hybridization demonstrated that two Brazilian G8P[6] rotavirus strains shared a high level of genomic RNA homology with Malawian G8P[6] strains, and a Brazilian G9P[8] strain was related most closely to a G9P[8] strain from India. The results suggest that certain rotavirus strains have a much wider global circulation than generally appreciated. Continued global spread of such strains might challenge the efficacy of current rotavirus vaccines.

Evolutionary history and global spread of the emerging g12 human rotaviruses

G12 rotaviruses were first detected in diarrheic children in the Philippines in 1987, but no further cases were reported until 1998. However, G12 rotaviruses have been detected all over the world in recent years. Here, we report the worldwide variations of G12 rotaviruses to investigate the evolutionary mechanisms by which they managed to spread globally in a short period of time. We sequenced the complete genomes (11 segments) of nine G12 rotaviruses isolated in Bangladesh, Belgium, Thailand, and the Philippines and compared them with the genomes of other rotavirus strains. Our genetic analyses revealed that after introduction of the VP7 gene of the rare G12 genotype into more common local strains through reassortment, a vast genetic diversity was generated and several new variants with distinct gene constellations emerged. These reassortment events most likely took place in Southeast Asian countries and spread to other parts of the world. The acquirement of gene segments from human-adapted rotaviruses might allow G12 to better propagate in humans and hence to develop into an important emerging human pathogen.

Molecular epidemiology of rotavirus diarrhea among children and adults in Nepal: detection of G12 strains with P[6] or P[8] and a G11P[25] strain

In anticipation of a rotavirus vaccine in Nepal, this study was undertaken to determine the distribution of the G and P serotypes and electropherotypes of rotaviruses in order to examine if there is any emerging serotype or unusual strain circulating in children and adults in Nepal. Of 1,315 diarrheal stool specimens, rotavirus was detected by an enzyme-linked immunosorbent assay in 116 (17%) of 666 patients less than 5 years of age, in 18 (7%) of 260 patients 5 to 14 years of age, and in 19 (5%) of 358 patients 15 years of age and older. Approximately 75% of rotavirus diarrhea occurred in children less than 5 years of age. Approximately 70% of rotaviruses found in each of the three age groups belonged to serotype G1P[8]. Interestingly, there were 29 (20%) G12 rotaviruses carrying either P[8] or P[6] and one (0.7%) G11 rotavirus carrying an unusual P[25] genotype. RNA polyacrylamide gel electrophoresis discriminated 19 strains (electropherotypes), among which there were three codominant strains carrying G1P[8] and long RNA patterns. Five electropherotypes were discriminated among G12 rotaviruses, all of which had long RNA patterns. The fact that 20% of rotaviruses were G12 strains carrying either P[8] or P[6] and had multiple electropherotypes suggest that G12 strains are not more rare strains but that they pose an emerging challenge to current and future vaccines. The presence of multiple strains as defined by electropherotypes suggests the richness of the rotavirus gene pool in Nepal, where unusual strains may continue to emerge.

Human rotavirus serotype G9, São Paulo, Brazil, 1996-2003

Diverse rotavirus strains are present, and frequency of G9 is high.

A total of 3,101 fecal specimens were collected during an 8-year survey for rotavirus infection in São Paulo, Brazil. Group A rotavirus was detected in 774 (25.0%) specimens. Of these, 431 strains (55.7%) were analyzed for G and P types by reverse transcription–polymerase chain reaction; G1 was the predominant serotype (68.2%), followed by G9 (17.2%), G4 (6.3%), G2 (1.2%), G3 (0.7%), mixed infection (1.8%), and untypeable (4.6%). Both rotavirus G and P types could be established in 332 strains (77.0%). We identified the 4 most common strains worldwide: P[8]G1 (66.6%), P[4]G2 (1.0%), P[8]G3 (0.6%), and P[8]G4 (7.2%). Among the single G9 strains detected, VP4 genotyping showed that P[8]G9 was the most prevalent, followed by P[4]G9 and P[6]G9. The emergence and high frequency of rotavirus G9 in São Paulo, Brazil, and other parts of the world will affect the development and evaluation of future vaccines.

Rotavirus vaccine: early introduction in Latin America-risks and benefits

Rotavirus infection is the cause of severe gastroenteritis of young children worldwide, leading to an estimate of 600,000 deaths a year. Efforts to develop an effective and safe vaccine resulted in licensing in 1998 of a live oral vaccine (RotaShield) that was withdrawn less than 1 year later when reports of cases of intussusception were linked to its application. This led to development of new rotavirus vaccine candidates that are currently in late phase III clinical trials. One of these vaccines, GlaxoSmithKline's Rotarix, was licensed in July 2004 to be used in Mexico. This review describes the general background for rotavirus vaccine development, the different vaccine candidates that have been tested or are currently being evaluated, the association of rotavirus vaccination with the bowel blockage known as intussuception, and discusses the benefits and risks of the fast-track introduction of Rotarix in Latin America, and particularly in Mexico.

Molecular characterization of a porcine Group A rotavirus strain with G12 genotype specificity

A porcine Group A rotavirus strain (RU172) was detected and molecularly characterized during a surveillance study conducted for rotavirus infection in a pig farm located in a suburban area of Kolkata City, India. The G12 genotype specificity of RU172 was revealed by PCR-based genotyping assays following addition of a G12 type-specific primer (designed in our laboratory to pick up G12 isolates from field samples) and was confirmed by sequence analysis of the VP7-encoding gene. The RU172 strain exhibited maximum VP7 identities of 93.6% to 94.5% with human G12 strains at the deduced amino acid level. In spite of its G12 genotype nature, RU172 appeared to be distinct from human G12 rotaviruses and, on phylogenetic analysis, formed a separate lineage with human G12 strains. Among the other gene segments analyzed, RU172 belonged to NSP4 genotype B, had a NSP5 and VP6 of porcine origin, and shared maximum VP4 identities with porcine P[7] rotaviruses (94.3%-95.4% at the deduced amino acid level). Therefore, to the best of our knowledge, this is the first report of detection of an animal rotavirus strain with G12 genotype specificity. Detection of strains like RU172 provides vital insights into the genomic diversity of Group A rotaviruses of man and animals.

A Rotavirus Vaccine for Infants: The Asian Experience

Introduction: Severe rotavirus gastroenteritis in children causes significant morbidity world- wide and substantial deaths in developing countries. Hence, a live attenuated vaccine Rotarix™ was developed with human strain RIX4414 of G1P1A P[8] specificity. RIX4414 trials in infants have begun in developed and developing countries worldwide. An overview of RIX4414 in developed and developing countries and prospects with this vaccine in Asia are presented. Methods: Completed RIX4414 trials have been reviewed. Results: Two oral doses of RIX4414 were well tolerated with a reactogenicity profile similar to placebo. RIX4414 was also highly immunogenic, e.g., in a dose-ranging study conducted in Singapore, 98.8% to100% of infants had a vaccine take after 2 doses. RIX4414 did not affect the immune response of simultaneously administered routine infant vaccines. RIX4414 significantly reduced severe rotavirus gastroen- teritis in settings where multiple serotypes including the emerging G9 type co-circulated. Conclusion: These encouraging results warrant further evaluation of the vaccine worldwide and especially in developing countries with the highest need. Therefore, evaluation of the Rotarix™ vaccine is continuing in large phase III trials in Asia and worldwide. Key words: Asia, Attenuated, Developing countries, Gastroenteritis, RIX4414

Rotavirus types in Europe and their significance for vaccination

The degree of diversity of cocirculating human rotavirus wild-type strains is high. This article reviews the occurrence and frequency of rotavirus types in European children younger than 5 years of age during the past 10-15 years. To enable greater understanding of the overall epidemiologic situation, rotavirus types found in animals in Europe are described. In addition, rotavirus types occurring in children outside Europe are considered. Taken together, these data provide an essential background to the development of rotavirus vaccines. The different concepts of immunization with the 2 main rotavirus candidate vaccines are briefly discussed, and their potential impact on the epidemiology of cocirculating rotavirus wild-type viruses is considered. A case is made for comprehensive surveillance of cocirculating human rotavirus types in Europe after the implementation of rotavirus vaccination.

Rotavirus diarrhea in children and adults in a southern city of Brazil in 2003: Distribution of G/P types and finding of a rare G12 strain

Between May and August in 2003, a total of 251 fecal samples were collected from children and adults with diarrhea (5 inpatients and 246 outpatients) at a private hospital in the city of Ponta Grossa, the state of Paraná, Brazil. Group A rotavirus was detected in 71 of 251 (28.3%) specimens: 55 (77.5%) from children under 5 years of age and 16 (22.5%) from individuals aged 6-72 years. All 71 strains exhibited a "long" RNA pattern when analyzed by PAGE. Sixty-one positive samples that yielded enough RNA were submitted to PCR genotyping. The most frequent G/P genotype combination detected was G1P[8] (86.9%; 53/61) followed by G9P[8] (3.3%; 2/61) and G12P[9] (1.6%; 1/61). Rotaviruses with G2, G3, G4, P[4], or P[6] specificity were not detected. For three strains (4.9%) bearing G1 genotype, the VP4 specificity could no be determined, and two specimens (3.3%) remained G/P non-typeable. One rotavirus strain (HC91) bearing G12P[9] genotype with a "long" electropherotype was isolated from an 11-month-old boy with diarrhea for the first time in Brazil. The cell-culture grown HC91 strain was shown to belong to serotype G12 by neutralization.

Coupling of Rotavirus Genome Replication and Capsid Assembly

The Reoviridae family represents a diverse collection of viruses with segmented double-stranded (ds)RNA genomes, including some that are significant causes of disease in humans, livestock, and plants. The genome segments of these viruses are never detected free in the infected cell but are transcribed and replicated within viral cores by RNA-dependent RNA polymerase (RdRP). Insight into the replication mechanism has been provided from studies on Rotavirus, a member of the Reoviridae whose RdRP can specifically recognize viral plus (+) strand RNAs and catalyze their replication to dsRNAs in vitro. These analyses have revealed that although the rotavirus RdRP can interact with recognition signals in (+) strand RNAs in the absence of other proteins, the conversion of this complex to one that can support initiation of dsRNA synthesis requires the presence and partial assembly of the core capsid protein. By this mechanism, the viral polymerase can carry out dsRNA synthesis only when capsid protein is available to package its newly made product. By preventing the accumulation of naked dsRNA within the cell, the virus avoids triggering dsRNA-dependent interferon signaling pathways that can induce expression and activation of antiviral host proteins.

Detection of group a human rotavirus G9 genotype circulating in Córdoba, Argentina, as early as 1980

The incidence of human rotavirus G types was determined over a 25-year period (1979-2003) by using reverse transcription-PCR (RT-PCR) to examine 519 stool specimens found to be positive for rotavirus by enzyme linked immunosorbent assay (ELISA) or polyacrylamide gel electrophoresis (PAGE). These stool samples were obtained from children under 3 years old who had been treated for acute diarrhea at public hospitals in Córdoba, Argentina. The present study describes the continued circulation of the common human G types G1 (53.8%), G2 (10.2%), G3 (4.4%), and G4 (27%), and also the detection of the unusual types G8 (0.5%) and G9 (4.2%). Genotype G9 was detected during the 1980-1988 and 1997-2003 periods at relatively low rates. Rotavirus G types distribution was independent of age (1-18 months), gender or out-patient or in-patient status. Unexpectedly, 44.6% of mixed infections were detected, involving common and unusual genotypes. Overall, 95.4% of the typed strains belonged to the most prevalent human serotypes (G1-G4) but the detection of G9 infection throughout this study period highlights the importance of this serotype as a human pathogen.

Rotavirus serotypes and electropherotypes identified among hospitalised children in São Luís, Maranhão, Brazil

During June 1997-June 1999 rotavirus infection was screened in infants aged up to 2 years and hospitalised with acute diarrhoea in São Luís, Northeastern Brazil. Altogether, 128 stool samples were collected from diarrhoeic patients and additional 122 faecal specimens from age- and- temporal matched inpatients without diarrhoea were obtained; rotavirus positivity rates for these groups were 32.0% (41/128) and 9.8% (12/122), respectively (p < 0.001). Both electropherotyping and serotyping could be performed in 42 (79.2%) of the 53 rotavirus-positive stool samples. Long and short electropherotypes were detected at similar rates - 38.1% and 40.5% of specimens, respectively. Overall, a G serotype could be assigned for 35 (83.3%) of specimens, the majority of them (66.7%) bearing G1-serotype specificity. Taking both electropherotypes and serotypes together, G1 rotavirus strains displaying long and short RNA patterns accounted for 30.9% and 19.0% of tested specimens, respectively; all G2 strains had short electropherotype. Rotavirus gastroenteritis was detected year-round and, in 1998, the incidence rates tended to be higher during the second semester than in the first semester: 45.2% and 26.1% (p = 0.13), respectively. Rotavirus infections peaked at the second semester of life with frequencies of 30.1% and 13.5% for diarrhoeic children and controls, respectively. While the six rotavirus strains bearing G2-type specificity were circulating throughout the whole study period, G1 serotypes (n = 27) emerged as from June 1998 onwards, 20 (74.1%) of which clustering in 1998. These data underscore the importance of rotaviruses in the aetiology of severe infantile gastroenteritis in Northeastern Brazil and sustain the concept that a future vaccine should confer protection against more than one serotype.