Detection of the emerging rotavirus G12P[8] genotype at high frequency in brazil in 2014: Successive replacement of predominant strains after vaccine introduction

Genetic diversity and evolution of G12P[6] DS-1-like and G12P[9] AU-1-like Rotavirus strains in Brazil

In the early 2000s, the global emergence of rotavirus (RVA) G12P[8] genotype was noted, while G12P[6] and G12P[9] combinations remained rare in humans. This study aimed to characterize and phylogenetically analyze three Brazilian G12P[9] and four G12P[6] RVA strains from 2011 to 2020, through RT-PCR and sequencing, in order to enhance our understanding of the genetic relationship between human and animal-origin RVA strains. G12P[6] strains displayed a DS-1-like backbone, showing a distinct genetic clustering. G12P[6] IAL-R52/2020, IAL-R95/2020 and IAL-R465/2019 strains clustered with 2019 Northeastern G12P[6] Brazilian strains and a 2018 Benin strain, whereas IAL-R86/2011 strain grouped with 2010 Northern G12P[6] Brazilian strains and G2P[4] strains from the United States and Belgium. These findings suggest an African genetic ancestry and reassortments with co-circulating American strains sharing the same DS-1-like constellation. No recent zoonotic reassortment was observed, and the DS-1-like constellation detected in Brazilian G12P[6] strains does not seem to be genetically linked to globally reported intergenogroup G1/G3/G9/G8P[8] DS-1-like human strains. G12P[9] strains exhibited an AU-1-like backbone with two different genotype-lineage constellations: IAL-R566/2011 and IAL-R1151/2012 belonged to a VP3/M3.V Lineage, and IAL-R870/2013 to a VP3/M3.II Lineage, suggesting two co-circulating strains in Brazil. This genetic diversity is not observed elsewhere, and the VP3/M3.II Lineage in G12P[9] strains seems to be exclusive to Brazil, indicating its evolution within the country. All three G12P[9] AU-1-like strains were closely relate to G12P[9] strains from Paraguay (2006-2007) and Brazil (2010). Phylogenetic analysis also highlighted that all South American G12P[9] AU-1-like strains had a common origin and supports the hypothesis of their importation from Asia, with no recent introduction from globally circulating G12P[9] strains or reassortments with local G12 strains P[8] or P[6]. Notably, certain genes in the Brazilian G12P[9] AU-1-like strains share ancestry with feline/canine RVAs (VP3/M3.II, NSP4/E3.IV and NSP2/N3.II), whereas NSP1/A3.VI likely originated from artiodactyls, suggesting a history of zoonotic transmission with human strains. This genomic data adds understanding to the molecular epidemiology of G12P[6] and G12P[9] RVA strains in Brazil, offering insights into their genetic diversity and evolution.

Genomic Constellation of Human Rotavirus G8 Strains in Brazil over a 13-Year Period: Detection of the Novel Bovine-like G8P[8] Strains with the DS-1-like Backbone

Rotavirus (RVA) G8 is frequently detected in animals, but only occasionally in humans. G8 strains, however, are frequently documented in nations in Africa. Recently, an increase in G8 detection was observed outside Africa. The aims of the study were to monitor G8 infections in the Brazilian human population between 2007 and 2020, undertake the full-genotype characterization of the four G8P[4], six G8P[6] and two G8P[8] RVA strains and conduct phylogenetic analysis in order to understand their genetic diversity and evolution. A total of 12,978 specimens were screened for RVA using ELISA, PAGE, RT-PCR and Sanger sequencing. G8 genotype represented 0.6% (15/2434) of the entirely RVA-positive samples. G8P[4] comprised 33.3% (5/15), G8P[6] 46.7% (7/15) and G8P[8] 20% (3/15). All G8 strains showed a short RNA pattern. All twelve selected G8 strains displayed a DS-1-like genetic backbone. The whole-genotype analysis on a DS-1-like backbone identified four different genotype-linage constellations. According to VP7 analysis, the Brazilian G8P[8] strains with the DS-1-like backbone strains were derived from cattle and clustered with newly DS-1-like G1/G3/G9/G8P[8] strains and G2P[4] strains. Brazilian IAL-R193/2017/G8P[8] belonged to a VP1/R2.XI lineage and were grouped with bovine-like G8P[8] strains with the DS-1-like backbone strains detected in Asia. Otherwise, the Brazilian IAL-R558/2017/G8P[8] possess a “Distinct” VP1/R2 lineage never previously described and grouped apart from any of the DS-1-like reference strains. Collectively, our findings suggest that the Brazilian bovine-like G8P[8] strains with the DS-1-like backbone strains are continuously evolving and likely reassorting with local RVA strains rather than directly relating to imports from Asia. The Brazilian G8P[6]-DS-1-like strains have been reassorted with nearby co-circulating American strains of the same DS-1 genotype constellation. However, phylogenetic analyses revealed that these strains have some genetic origin from Africa. Finally, rather than being African-born, Brazilian G8P[4]-DS-1-like strains were likely imported from Europe. None of the Brazilian G8 strains examined here exhibited signs of recent zoonotic reassortment. G8 strains continued to be found in Brazil according to their intermittent and localized pattern, thus, does not suggest that a potential emergence is taking place in the country. Our research demonstrates the diversity of G8 RVA strains in Brazil and adds to the understanding of G8P[4]/P[6]/P[8] RVA genetic diversity and evolution on a global scale.

Pathogen evolution during vaccination campaigns

Following the initiation of the unprecedented global vaccination campaign against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), attention has now turned to the potential impact of this large-scale intervention on the evolution of the virus. In this Essay, we summarize what is currently known about pathogen evolution in the context of immune priming (including vaccination) from research on other pathogen species, with an eye towards the future evolution of SARS-CoV-2.

Surveillance and molecular characterization of human sapovirus in patients with acute gastroenteritis in Brazil, 2010 to 2017

BACKGROUND

Human sapoviruses (HuSaV) are associated with acute gastroenteritis (AGE), causing sporadic cases and outbreaks in patients worldwide. In Brazil, however, there are few reports describing the prevalence of HuSaV in patients with AGE.

OBJECTIVE

Describing the diversity of HuSaV in Brazil by detecting and molecularly characterizing HuSaV among patients with AGE during an 8-year period (2010-2017).

STUDY DESIGN

A total of 3974 stool samples, testing negative for rotavirus (RVA), norovirus (NoV) and human adenovirus (HAdV), were selected and screened for the presence of HuSaV. Nested RT-PCR were performed for a partial region of VP1, sequenced and genetic analyzed for genotyping the positive samples.

RESULTS

In the current study, the HuSaV prevalence was determined to be 3.7% (149/3974). A higher prevalence, 5.7% (118/2074), was observed in children under 2 years of age. During the surveillance period, 13 outbreaks were detected: 12 outbreaks in children under 3 years old and one outbreak in adults. Among the 149 HuSaV positive cases, 106 samples (71%) were successfully sequenced. The most prevalent genotype found was GI.1 (44.3%), followed by GI.2 (21.7%), GI.3 (3.8%), GI.6 (2.8%), GII.1 (5.7%), GII.2 (8.5%), GII.3 (2.8%), GII.4 (2.8%), GII.5 (5.7%) and GIV.1 (1.9%). Two GIV.1 strains characterized in this study are, to date, the only strains of this genotype reported in Brazil.

CONCLUSIONS

The present study elucidated the circulation of HuSaV in Brazil and highlight that HuSaV has not assumed an epidemiological importance in the country after the introduction of the RVA vaccine.

Genotype Diversity before and after the Introduction of a Rotavirus Vaccine into the National Immunisation Program in Fiji

The introduction of the rotavirus vaccine, Rotarix, into the Fiji National Immunisation Program in 2012 has reduced the burden of rotavirus disease and hospitalisations in children less than 5 years of age. The aim of this study was to describe the pattern of rotavirus genotype diversity from 2005 to 2018; to investigate changes following the introduction of the rotavirus vaccine in Fiji. Faecal samples from children less than 5 years with acute diarrhoea between 2005 to 2018 were analysed at the WHO Rotavirus Regional Reference Laboratory at the Murdoch Children's Research Institute, Melbourne, Australia, and positive samples were serotyped by EIA (2005-2006) or genotyped by heminested RT-PCR (2007 onwards). We observed a transient increase in the zoonotic strain equine-like G3P[8] in the initial period following vaccine introduction. G1P[8] and G2P[4], dominant genotypes prior to vaccine introduction, have not been detected since 2015 and 2014, respectively. A decrease in rotavirus genotypes G2P[8], G3P[6], G8P[8] and G9P[8] was also observed following vaccine introduction. Monitoring the rotavirus genotypes that cause diarrhoeal disease in children in Fiji is important to ensure that the rotavirus vaccine will continue to be protective and to enable early detection of new vaccine escape strains if this occurs.

Genomic constellation of human Rotavirus A strains identified in Northern Brazil: a 6-year follow-up (2010-2016)

Surveillance of Rotavirus A (RVA) throughout the national territory is important to establish a more complete epidemiological-molecular scenario of this virus circulation in Brazil. The aim of the present study was to investigate the genetic diversity of RVA strains circulating in Tocantins State (Northern Brazil) during six years of post-vaccination follow-up (2010-2016). A total of 248 stool samples were screened by next generation sequencing and 107 (43.1%) nearly full length RVA genome sequences were obtained; one sample was co-infected with two RVA strains (G2/G8P[4]). Six G and P genotypes combinations were detected: G12P[8] strains (78.6%), as well as the G3P[8] (9.3%) and G1P[8] (0.9%) were associated with a Wa-like genogroup backbone. All G2P[4] (5.6%) and G8P[4] (2.8%) strains, including the mixed G2/G8P[4] infection (0.9%) showed the DS-1-like genetic background. The two G12P[4] strains (1.9%) were associated with distinct genetic backbones: Wa-like and DS-1-like. The phylogenetic analysis revealed the circulation of lineages G1-I, G2-IV, G3-III, G8-I and G12-III, and P[4]-V and P[8]-III of the VP7 and VP4 genes, respectively. Conserved clustering pattern and low genetic diversity were observed regarding VP1-VP3 and VP6, as well as NSP1-5 segments. We identified the same RVA circulation pattern reported in other Brazilian regions in the period of 2010-2016, suggesting that rural and low-income areas may not have a different RVA genotypic distribution compared to other parts of the country. The unique presentation of whole-genome data of RVA strains detected in the Tocantins State provides a baseline for monitoring variations in the genetic composition of RVA in this area.

Genomic analysis of group A rotavirus G12P[8] including a new Japanese strain revealed evidence for intergenotypic recombination in VP7 and VP4 genes

Group A rotavirus is a leading cause of severe acute gastroenteritis worldwide. In this study, the first complete coding sequences of 11 RNA segments of human group A rotavirus G12P[8] in Japan were determined by an unbiased viral metagenomics. Its genomic constellation (VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes) was identified as G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. When performing the genetic analysis, we discovered an intergenotypic recombination event in the pig group A rotavirus G12P[8] strain BUW-14-A008. The novel recombination was found between two different genotypes G12 and G3 in the VP7 gene, and P[8] and P[13] in the VP4 gene.

Genotype distribution of Group A rotavirus in children before and after massive vaccination in Latin America and the Caribbean: Systematic review

BACKGROUND

During the last decade, most of Latin American and the Caribbean (LAC) countries have implemented oral live rotavirus vaccines in their national vaccination programs with remarkable results. However, it has been suggested that massive vaccination could lead to the replacement of circulating genotypes or the emergence of new variants or neutralizing antibodies escape mutants, which may reduce the effectiveness of the vaccine. The objective was to analyze the genetic diversity of Group A rotavirus before and after the introduction of universal vaccination in LAC.

METHODS

We conducted a systematic review of studies published in PubMed, Scielo and LILACS. There were considered only LAC countries with rotavirus massive vaccination strategy which had described circulating genotypes data in children under 5 years of age, either for surveillance or vaccine effectiveness purposes, from 2001 to 2017. Systematic review stages were carried out following the recommendations of PRISMA.

RESULTS

Of the 18 countries that included any of the two licensed rotavirus vaccines in their national schedules since 2006, only 7 (~39%) presented studies of RVA genetic diversity before and after implementation, and met the inclusion criteria. Four of them (Argentina, Brazil, Colombia and Nicaragua) experienced a rapid switch from Wa-like to DS-1-like strains. Also, G1P[8] association, considered the most predominant worldwide in the pre-vaccination era, decreased significantly and was only frequently detected in Venezuela and Nicaragua. No defined pattern of emergence at high frequencies of unusual associations was observed in the post vaccination period, except for some evidence of G9P[4] in Colombia, G3P[6] and G1P[4] in Nicaragua.

CONCLUSIONS

Even though the evidence shows a DS-1-like change trend, data from studies conducted in Latin America and the Caribbean are diverse and still not sufficient to assess the impact of vaccines on viral ecology or if genetic diversity is influenced by natural mechanisms of fluctuation.

Rotavirus A Infections in Community Childhood Diarrhea in the Brazilian Semiarid Region During Postvaccination Era

BACKGROUND

Rotavirus A (RVA) is one of the leading causes of acute gastroenteritis worldwide; however, few studies assessed RVA genetics with community surveillance.

OBJECTIVES

This study aimed to investigate clinical data, genetic diversity, and coinfection patterns of RVA infections in children from 2 to 36 months old with or without community childhood diarrhea in the Brazilian semiarid region during postvaccination era.

METHODS

We enrolled and collected socioeconomic/clinical information using a standardized questionnaire and fecal samples from 291 children. Viral RNA samples were extracted and analyzed using quantitative reverse transcription polymerase chain reaction to establish the diagnosis of RVA. Sequencing of VP7 and VP4 (VP8*) regions and phylogenetic analysis were performed.

RESULTS

RVA-negative diagnosis was associated with children 24 to 36 months old with complete vaccination schedule. Genotype G1P[8] was the most prevalent (57%), whereas unusual genotypes including G1P[4], G2P[8], and G3P[9] were also detected. G1- and P[8]-positive samples showed high degrees of similarity with the vaccine strain. RVA coinfections were frequently observed, and enteroaggregative Escherichia coli was the most prevalent copathogen.

CONCLUSIONS

These results demonstrate that genotype G1P[8] is the most prevalent strain. VP7 and/or VP8* gene segments arising from RV1 vaccine strain were documented in these children, suggesting shedding or herd vaccination. Moreover, our study indicates full vaccination is important for protection against RVA infections.

Genetic analysis of Ghanaian G1P[8] and G9P[8] rotavirus A strains reveals the impact of P[8] VP4 gene polymorphism on P-genotyping

The World Health Organisation rotavirus surveillance networks have documented and shown eclectic geographic and temporal diversity in circulating G- and P- genotypes identified in children <5 years of age. To effectively monitor vaccine performance and effectiveness, robust molecular and phylogenetic techniques are essential to detect novel strain variants that might emerge due to vaccine pressure. This study inferred the phylogenetic history of the VP7 and VP4 genes of previously non-typeable strains and provided insight into the diversity of P[8] VP4 sequences which impacted the outcome of our routine VP4 genotyping method. Near-full-length VP7 gene and the VP8* fragment of the VP4 gene were obtained by Sanger sequencing and genotypes were determined using RotaC v2.0 web-based genotyping tool. The genotypes of the 57 rotavirus-positive samples with sufficient stool was determined. Forty-eight of the 57 (84.2%) had the P[8] specificity, of which 43 (89.6%) were characterized as P[8]a subtype and 5 (10.4%) as the rare OP354-like subtype. The VP7 gene of 27 samples were successfully sequenced and their G-genotypes confirmed as G1 (18/27) and G9 (9/27). Phylogenetic analysis of the P[8]a sequences placed them in subcluster IIIc within lineage III together with contemporary G1P[8], G3P[8], G8P[8], and G9P[8] strains detected globally from 2006-2016. The G1 VP7 sequences of the study strains formed a monophyletic cluster with African G1P[8] strains, previously detected in Ghana and Mali during the RotaTeq vaccine trial as well as Togo. The G9 VP7 sequences of the study strains formed a monophyletic cluster with contemporary African G9 sequences from neighbouring Burkina Faso within the major sub-cluster of lineage III. Mutations identified in the primer binding region of the VP8* sequence of the Ghanaian P[8]a strains may have resulted in the genotyping failure since the newly designed primer successfully genotyped the previously non-typeable P[8] strains. In summary, the G1, G9, and P[8]a sequences were highly similar to contemporary African strains at the lineage level. The study also resolved the methodological challenges of the standard genotyping techniques and highlighted the need for regular evaluation of the multiplex PCR-typing method especially in the post-vaccination era. The study further highlights the need for regions to start using sequencing data from local rotavirus strains to design and update genotyping primers.

First Detection of DS-1-like G1P[8] Double-gene Reassortant Rotavirus Strains on The American Continent, Brazil, 2013

Emergence of DS-1-like-G1P[8] rotavirus in Asia have been recently reported. We report for the first time the detection and the whole genome phylogenetic analysis of DS-1-like-G1P[8] strains in America. From 2013 to 2017, a total of 4226 fecal samples were screened for rotavirus by ELISA, PAGE, RT-PCR and sequencing. G1P[8] represented 3.7% (30/800) of all rotavirus-positive samples. DS-1-like-G1P[8] comprised 1.6% (13/800) detected exclusively in 2013, and Wa-like-G1P[8] comprised 2.1% (17/800) detected from 2013 to 2015. Whole genome sequencing confirmed the DS-1-like backbone I2-R2-C2-M2-A2-N2-T2-E2-H2. All genome segments of the Brazilian DS-1-like-G1P[8] strains clustered with those of Asian strains, and apart from African DS-1-like-G1P[8] strains. In addition, Brazilian DS-1-like-G1P[8] reassortants distantly clustered with DS-1-like backbone strains simultaneously circulating in the country, suggesting that the Brazilian DS-1-like-G1P[8] strains are likely imported from Asia. Two distinct NSP4 E2 genotype lineages were also identified, indicating the existence of a co-circulating pool of different DS-1-like G1P[8] strains. Surveillance systems must be developed to examine if RVA vaccines are still effective for the prevention against unusual DS-1-like-G1P[8] strains.

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.

The evolving epidemiology of rotavirus A infection in Brazil a decade after the introduction of universal vaccination with Rotarix®

Background

Brazil introduced the monovalent rotavirus vaccine (Rotarix®) in 2006. This study aimed to assess the epidemiology and genotype distribution of species-A rotavirus (RVA) in Brazil, comparing the pre- and post-vaccination periods.

Methods

Laboratory-based RVA surveillance included 866 municipalities in 22 Brazilian states, over a 21-year period. A total of 16,185 children with diarrheal diseases (DD) aged up to 12 years between 1996 and 2005 (pre-vaccination period, n = 7030) and from 2006 to 2017 (post-vaccination period, n = 9155) were enrolled. RVA was detected using ELISA immune assay and/or polyacrylamide gel electrophoresis and genotyped using nested PCR and/or nucleotide sequencing. RVA-positivity and genotypes detection rates were compared in distinct periods and age groups and Rotarix vaccination status.

Results

RVA-positivity in pre- and post-vaccination periods was, respectively: 4–11 months bracket, 33.3% (668/2006) and 16.3% (415/2547) (p <  0.001); 12–24 months, 28.2% (607/2154) and 22.2% (680/3068) (p <  0.001); 25–48 months, 17.4% (215/1235) and 29.4% (505/1720) (p <  0.001). Genotypes distribution in the pre- and post-vaccination periods was, respectively: G1P [8]/G1P[Not Typed], 417/855 (48.8%) and 118/1835 (6.4%) (p <  0.001); G2P [4]/G2P[NT], 47/855 (5.5%) and 838/1835 (45.7%) (p <  0.001); G3P [8]/G3P[NT], 55/855 (6.4%) and 253/1835 (13.8%) (p <  0.001); G9P [8]/G9P[NT], 238/855 (27.8%) and 152/1835 (8.3%) (p <  0.001); G12P [8]/G129P[NT], 0/871 (0%) and 249/1835(13.6%) (p <  0.001). Concerning infants aged 4–11 months, RVA frequency in fully vaccinated and non-vaccinated individuals was 11.9% (125/1052) and 24.5% (58/237) (p <  0.001), respectively. In children aged 12–24 months, RVA detection rate was 18.1% (253/1395) and 29.6% (77/260) (p <  0.001), for the vaccinated and non-vaccinated individuals, respectively (p <  0.001).

Conclusions

RVA infection was significantly less frequent in children aged ≤2 years with DD after implementing vaccination, mainly among vaccinated children. It was also observed a decrease of P [8] circulation and emergence of G2P[4] in 2005, and afterwards in the post-vaccine era, with spreading of G12P[8] in 2014–2015 and of G3P[8] in 2017. Continuous RVA surveillance must be carried out in this scenario.

Spread of the emerging equine-like G3P[8] DS-1-like genetic backbone rotavirus strain in Brazil and identification of potential genetic variants

In 2013, the equine-like G3P[8] DS-1-like rotavirus (RVA) strain emerged worldwide. In 2016, this strain was reported in northern Brazil. The aims of the study were to conduct a retrospective genetic investigation to identify the possible entry of these atypical strains in Brazil and to describe their distribution across a representative area of the country. From 2013 to 2017, a total of 4226 faecal samples were screened for RVA by ELISA, PAGE, RT-PCR and sequencing. G3P[8] represented 20.9 % (167/800) of all RVA-positive samples, further subdivided as equine-like G3P[8], DS-1-like (11.0 %; 88/800) and Wa-like G3P[8] (9.9 %; 79/800). Six equine-like G3P[8] DS-1-like samples were selected for whole-genome investigation, confirming the backbone I2-R2-C2-M2-A2-N2-T2-E2-H2. During 2013-2014, Wa-like G3P[8] was predominant and no equine-like G3P[8] DS-1-like was detected. Equine-like G3P[8] DS-1-like was first identified in Paraná in March/2015, suggesting that the strain entered Brazil through the Southern region. Equine-like G3P[8] rapidly spread across the area under surveillance and displayed a marked potential to replace Wa-like G3P[8] strains. Brazilian equine-like G3P[8] DS-1-like strains clustered with contemporary equine-like G3P[8] DS-1-like detected worldwide, but exhibited a distinct NSP2 genotype (N2) compared to the previously reported Amazon equine-like G3P[8] DS-1-like strain (N1). Two distinct NSP4 E2 genotype lineages were also identified. Taken together, these data suggest that different variants of equine-like G3P[8] DS-1-like strains might have been introduced into the country at distinct time points, and co-circulated in the period 2015-2017. The global emergence of equine-like G3P[8] DS-1-like strains, predominantly in countries using the Rotarix vaccine, raises the question of whether vaccines may be inducing selective pressures on zoonotic strains.

A one-step real-time RT-PCR helps to identify mixed rotavirus infections in Mexico

Rotaviruses continue being the most important pathogens responsible of diarrhea in young children worldwide. Seminested reverse transcription polymerase chain reaction (RT-PCR) is used to determine rotavirus genotype; however, this technique employs multistep procedures. The real-time RT-PCR is a fast and reliable tool that can be used as rotavirus genotyping tool, especially in rotavirus outbreaks. In this study, we tested a real-time RT-PCR to identify rotavirus genotype using a panel of 252 samples from patients with diarrheal disease caused by G9P[4] and G12P[8] genotypes, which were identified as emerging rotaviruses in 2 outbreaks in Chiapas, Mexico. Our results show that the real-time RT-PCR assay detected these rotaviruses, and it allowed us to identify mixed genotype infections, G/P combinations, and the viral abundance in some samples in which the seminested assay could not identify them. Therefore, the real-time RT-PCR is a molecular tool that can be great support during rotavirus outbreaks.

Phylogenetic analysis of G1P[8] and G12P[8] rotavirus A samples obtained in the pre- and post-vaccine periods, and molecular modeling of VP4 and VP7 proteins

Reduction in morbimortality rates for acute gastroenteritis (AGE) by Rotavirus A (RVA) has been observed after the introduction of vaccines, however the agent continues to circulate. The present study described the genomic characterization of the 11 dsRNA segments of two RVA samples G1P[8] obtained in the pre- and post-vaccination periods and one of G12P[8] sample (post-vaccine), compared to Rotarix™ vaccine. Analysis by molecular sequencing of the samples showed that the three samples belonged to genogroup I. In addition, the analysis of VP7 gene revealed that the samples G1 (pre-vaccine), G1 (post-vaccine) and G12 were characterized as lineages II, I and III, respectively. Regarding to VP4 and NSP4 gene it was observed that all samples belonged to lineage III, whereas for VP6 gene, the sample of the pre- and post-vaccine belonged to the lineage IV and I, respectively. Considering the VP7 gene, it was observed high nucleotide and amino acid identity for the two G1 samples when compared to Rotarix™ vaccine and lesser identity for the G12 sample. In relation to antigenic epitope of VP7 greater modifications were observed for the G12 sample in the 7-2 epitope that was confirmed by molecular modeling. On the other hand, for VP4, some changes in the 8-1 and 8-3 antigenic epitopes was observed for the three samples. This data could be interpreted as a low selective pressure exerted by vaccination in relation to G1P[8] samples and lesser protection in relation to G12P[8]. Thus, the continuous monitoring of RVA circulating samples remains important.

Group A rotavirus gastroenteritis: post-vaccine era, genotypes and zoonotic transmission

This article provides a review of immunity, diagnosis, and clinical aspects of rotavirus disease. It also informs about the changes in epidemiology of diarrheal disease and genetic diversity of circulating group A rotavirus strains following the introduction of vaccines. Group A rotavirus is the major pathogen causing gastroenteritis in animals. Its segmented RNA genome can lead to the emergence of new or unusual strains in human populations via interspecies transmission and/or reassortment events.

VP7 and VP8* genetic characterization of group A rotavirus genotype G12P[8]: Emergence and spreading in the Eastern Brazilian coast in 2014

Group A rotavirus (RVA) genotype G12 is habitually associated with diarrhea disease (DD) in African children and recently its detection has increased worldwide. A total of 970 stool samples collected from individuals with DD in the Northeastern, Southeastern, and Southern Brazilian regions, Eastern coast, were analyzed and 321 (33%) were positive for RVA and of these, 241 (75%) genotyped as G12P[8]. The rate of RVA positivity was higher among children aged 5-10 years old (60%). All RVA infections observed in adults aged >21 years were G12P[8] (n = 27) showing that this genotype affected older age groups during the year of 2014 in Brazil. Phylogenetic analysis of VP7 and VP8* G12P[8] strains demonstrated an elevated similarity among Brazilian and G12-III prototypes strains circulating worldwide recently, suggesting that this lineage is associated with the global spread of the G12 genotype, considered as the 6th most prevalent human RVA genotype nowadays; while other G12 lineages remain sporadically detected and usually detected in association with other P genotypes. VP8* analysis revealed that Brazilian strains belong to P[8]-3 lineage, the single P[8] lineage presently detected in the country. No major nucleotide/amino acid disparities were observed among strains recovered from children and adults for VP7 and VP8* genes. These data are essential to support the surveillance studies, particularly in countries where the RVA vaccine was introduced in their National Immunization Program enabling identification of potential alterations in the epidemiological profile that can impact its efficacy in vaccination programs. J. Med. Virol. 89:64-70, 2017. © 2016 Wiley Periodicals, Inc.

Epidemiology of rotavirus A diarrhea in Chókwè, Southern Mozambique, from February to September, 2011

Acute diarrhea disease caused by Rotaviruses A (RVA) is still the leading cause of morbidity and mortality in children ≤5 years old in developing countries. An exploratory cross-sectional study was conducted between February and September, 2011 to determine the proportion of acute diarrhea caused by RVA. A total of 254 stool specimens were collected from children ≤5 years old with acute diarrhea, including outpatients (222 children) and inpatients (32 children), in three local health centers in Chókwè District, Gaza Province, South of Mozambique. RVA antigens were detected using enzyme immunoassay (EIA); the RVA G (VP7) and P (VP4) genotypes were determined by RT-PCR or analysis sequencing. Sixty (24%) out of 254 fecal specimens were positive for RVA by EIA; being 58 (97%) from children ≤2 years of age. RVA prevalence peaks in June and July (coldest and drier months) and the G[P] binary combination observed were G12P[8] (57%); G1P[8] (9%); G12P[6] (6%); and 2% for each of the following genotypes: G1P[6], G2P[6] G4P[6], and G9P[8]. Non-Typeable (NT) G and/or P genotypes were observed as follows: G12P [NT] (6%); G1P [NT], G3P[NT] and GNTP[NT] (4%). Considering the different GP combinations, G12 represented 67% of the genotypes. This is the first data showing the diversity of RVA genotypes in Mozambique highlighting the epidemiological importance of these viruses in acute diarrhea cases in children ≤2 years old. In addition, these findings will provide a baseline data before the introduction of the RVA monovalent (Rotarix(®) ) vaccine in the National Immunization Program in September 2015. J. Med. Virol. 88:1751-1758, 2016. © 2016 Wiley Periodicals, Inc.