Detection and molecular characterization of group A rotavirus from hospitalized children in Rio de Janeiro, Brazil, 2004

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 in adults, Brazil, 2004–2011: G2P[4] dominance and potential impact on vaccination

Objectives

The aim of this study was to monitor rotavirus (RV) infections in adults >18 years with acute gastroenteritis during 2004–2011 national Brazilian RV surveillance. In addition, to characterize the RV group A (RVA) strains in order to gain insight into the supposed vaccine selective pressure imposed to Brazilian children population.

Methods

A total of 2102 convenient fecal specimens were investigated by ELISA, PAGE, and RT-PCR.

Results

RV was detected in 203 (9.6%) of 2102 specimens, and showed a marked peak of detection in September. RVA infection was detected in 9.4% (197/2102) and RV group C (RVC) in 0.3% (6/2102). The most frequent genotypes detected in 2004 and 2005 were G9P[8] (38.5%; 5/13) and G1P[8] (54.5%; 6/11), respectively. The dominant genotype identified from 2006 to 2011 was G2P[4] (64.4%; 116/180). Detection rate varied during the 8-year period of the study from 0.7% to 12.9%.

Conclusion

The high detection rate of G2P[4] in adults provides further evidence that its dominance reflects the seasonality of RVA strains instead of the supposed selective advantage created by vaccination program. It also can be suggested that adult infections may serve as a reservoir to maintain RVA strains in childhood gastroenteritis. Considering the detection rate, the evident reduction of RVA frequency observed in children after vaccine introduction was not present in adults.

Molecular characterization of rotavirus genotypes in immunosuppressed and non-immunosuppressed pediatric patients

OBJECTIVE

To describe the genotypic variability of group A rotavirus (RVA) found in immunosuppressed and non-immunosuppressed pediatric patients treated at the Hospital de Clínicas da Universidade Federal do Paraná (HC-UFPR), Curitiba, Paraná.

METHODS

A cross-sectional study was conducted with 1,140 stool samples collected from April, 2001 to December, 2008 in outpatients and hospitalized patients with acute gastroenteritis referred to the hospital. RVA diagnosis was performed through the latex agglutination method and enzyme immunoassay. Reverse transcription followed by multiplex hemi-nested polymerase chain reaction (PCR) and nucleotide sequencing were used for genotype characterization. Genotype combinations, clinical, epidemiological, laboratory data, and presence of hospital-acquired infections were reported.

RESULTS

A total of 80 rotavirus-positive stool samples were analyzed. The most frequent associations between genotypes G and P were: G4 P[8] (38.9%), G1 P[8] (30.5%), G9 P[8] (13.9%), G2 P[4] (6.9%), and G3 P[8] (1.4%). G2 P[4] was the most prevalent genotype after the vaccine implementation in the years 2006 and 2008. A total of 62,5% of infected children were aged less than 12 months. Of these, 55.6% had severe dehydration and 26.7% needed intensive care. A frequency of 12.5% of nosocomial infections was found. No correlation was observed between genotype and severity of infection in the study patients.

CONCLUSION

RVA infections can be associated with severe clinical manifestations, and the surveillance of genotypic variability of this virus is crucial to monitor the emergence of new strains and the impact of the immunization in these patients.

Characterization of rotavirus causing acute diarrhoea in children in Kathmandu, Nepal, showing the dominance of serotype G12

Diarrhoeal diseases are a major problem in developing countries. Though precise data on childhood mortality associated with diarrhoeal diseases in Nepal are not available, it has been estimated that approximately 25 % of child deaths are associated with diarrhoeal disease, particularly acute diarrhoea. The purpose of this study was to assess the incidence of rotavirus causing acute diarrhoea in children less than 5 years of age. A total of 525 children with acute diarrhoea in a children's hospital of Kathmandu, Nepal, were enrolled between April and September 2011. The incidence of acute diarrhoea due to rotavirus was 25.9 % (136/525) as determined by ELISA. The percentage of rotavirus-infected males was higher (64.5 %) than females (35.5 %). The frequency of rotavirus cases was higher in children less than 2 years of age, among which the majority of cases (80.2 %) were in children between 6 and 24 months old (P<0.01). Genotypic characterization by RT-PCR revealed that the serotype G12 represented 55.9 % of cases in this study associated with P-types of either P[6], P[4] or P[8]. Further to this, a total of eight G/P combinations were identified, G12P[6] being the most common strain type of rotavirus in Nepal, with a prevalence rate of 46.4 %. The aim of this study was to find out the major genotypes of rotavirus causing acute diarrhoea in children.

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.

Analysis of human P[4]G2 rotavirus strains isolated in Brazil reveals codon usage bias and strong compositional constraints

The Rotavirus genus belongs to the family Reoviridae and its genome consist of 11 segments of double-stranded RNA. Group A rotaviruses (RV-A) are the main etiological agent of acute viral gastroenteritis in infants and young children worldwide. Understanding the extent and causes of biases in codon usage is essential to the understanding of viral evolution. However, the factors shaping synonymous codon usage bias and nucleotide composition in human RV-A are currently unknown. In order to gain insight into these matters, we analyzed the codon usage and base composition constraints on the two genes that codify the two outer capsid proteins (VP4 [VP8*] and VP7) of 58 P[4]G2 RV-A strains isolated in Brazil and investigated the possible key evolutionary determinants of codon usage bias. The results of these studies revealed that the frequencies of codon usage in both RV-A proteins studied are significantly different than the ones used by human cells. In order to observe if similar trends of codon usage are found when RV-A complete genomes are considered, we compare these results with results found using a dataset of 10 reference strains for whom the complete codes of the 11 segments are known. Similar results were obtained using capsid proteins or complete genomes. The general correlations found between the position of each sequence on the first axis generated by correspondence analysis and the relative dinucleotide abundances indicate that codon usage in RV-A can also be strongly influenced by underlying biases in dinucleotide frequencies. CpG and GpC containing codons are markedly suppressed. Thus, the results of this study suggest that RV-A genomic biases are the result of the evolution of genome composition in relation to host adaptation and the ability to escape antiviral cell responses.

Rotavirus genotype distribution after vaccine introduction, Rio de Janeiro, Brazil

Brazil introduced rotavirus vaccination in March 2006. We studied 133 rotavirus-positive fecal samples collected from February 2005 through December 2007. Genotype G2P[4] was found in 1.4% of samples in 2005, in 44% in 2006, and in 96% in 2007. Rotavirus detection rate decreased from 38% in 2005 to 24% in 2007 (p = 0.012).

Changing epidemiology of rotavirus-related hospitalizations in rio de janeiro, Brazil, from 2002 to 2006

A prospective hospital-based sentinel study conducted in Rio de Janeiro identified a shift in the pattern (long to short electropherotype and P(8) to P(4) genotype) of rotavirus strains recovered from children with severe diarrhea a few months after the far-reaching Brazilian rotavirus immunization program was launched, posing new interesting challenges.

Prevalence of enteropathogenic viruses and molecular characterization of group A rotavirus among children with diarrhea in Dar es Salaam Tanzania

Background

Different groups of viruses have been shown to be responsible for acute diarrhea among children during their first few years of life. Epidemiological knowledge of viral agents is critical for the development of effective preventive measures, including vaccines.

Methods

In this study we determined the prevalence of the four major enteropathogenic viruses – rotavirus, norovirus, adenovirus and astrovirus – was determined in 270 stool samples collected from children aged 0 – 60 months who were admitted with diarrhea in four hospitals in Dar es Salaam, Tanzania, using commercially available ELISA kits. In addition, the molecular epidemiology of group A rotavirus was investigated using reverse transcriptase multiplex polymerase chain reaction (RT-PCR).

Results

At least one viral agent was detected in 87/270 (32.2%) of the children. The prevalence of rotavirus, norovirus, adenovirus and astrovirus was 18.1%, 13.7%, 2.6% and 0.4%, respectively. In most cases (62.1%) of viruses were detected in children aged 7–12 months. The G and P types (VP7 and VP4 genotypes respectively) were further investigated in 49 rotavirus ELISA positive samples. G9 was the predominant G type (81.6%), followed by G1 (10.2%) and G3 (0.2%). P[8] was the predominant P type (83.7%), followed by P[6] (0.4%) and P[4] (0.2%). The following G and P types were not detected in this study population; G2, G4, G8 G10, P[9], P[10] and P[11]. The dominating G/P combination was G9P[8], accounting for 39 (90.7%) of the 43 fully characterized strains. Three (6.1%) of the 49 rotavirus strains could not be typed.

Conclusion

Nearly one third of children with diarrhea admitted to hospitals in Dar es Salaam had one of the four viral agents. The predominance of rotavirus serotype G9 may have implication for rotavirus vaccination in Tanzania.

Rotavirus and adenovirus in Rondônia

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viral gastroenteritis is a global problem in infants and young children. In this study the incidence of diarrhea was assessed in 877 hospitalized children under five years old, over a period of 24 months and distributed in 470 cases of diarrhea and 407 age-matched group with other pathologies, as control group. Two antigen detection techniques based on enzyme immunoassay (EIA) and latex particles were used for detection of rotavirus and adenovirus. Rotavirus A was a major cause of gastroenteritis with 23.6% of cases, being 90% of these cases in young children. Adenovirus infections was detected by EIA with frequency of 6.4%. Rotavirus and adenovirus were detected in 10.1 and 1.7% of stools from control group, respectively. Interestingly, the frequency of the youngest children in the control group excreting Rotavirus A was comparable to that detected in stools from diarrheic children. We cannot rule out the existence of other enteric viruses because the etiology of 171 cases of diarrhea was not determined and active search for astrovirus and calicivirus was not done. This is the first study that shows the presence of enteric viruses in the infantile population from Western Brazilian Amazonia and it was important to help physicians in the treatment of viral gastroenteritis.

Prevalence and molecular epidemiology of noroviruses in hospitalized children with acute gastroenteritis in Rio de Janeiro, Brazil, 2004

BACKGROUND

The role of noroviruses (NoV) as a cause of gastroenteritis outbreaks is well documented; however, the importance of NoV infections in hospitalized children is not well established. The aim of this study was to determine the prevalence and the genetic diversity of NoV in hospitalized children.

METHODS

Three-hundred eighteen fecal samples were collected from January to December 2004, from children with acute gastroenteritis in 3 public hospitals in Rio de Janeiro, Brazil. The prevalence and genetic diversity of NoV was carried out by using genome amplification and sequencing of polymerase and capsid genes.

RESULTS

NoV infections were detected in 65 (20%) of the samples, of which 11 (4%) were mixed infections with rotavirus. Infants up to 1-year-old were the most affected and a peak of virus detection was observed in autumn and spring seasons. Dehydration and diarrhea were the inclusion criterion; coughing (51%), vomiting (33%), and fever (22%) were the main clinical manifestations. Phylogenetic analysis showed that Genogroup II and GII/4 were prevalent. Two potential recombinant strains based in the different clustering pattern were observed.

CONCLUSIONS

This study demonstrated the importance of NoV infections causing severe acute gastroenteritis in hospitalized children in Rio de Janeiro, Brazil. Molecular epidemiology surveillance determining the circulation pattern of different genotypes and recombinant strains is helpful for designing prevention strategies of NoV transmission in children. Studies concerning the prevalence and the molecular epidemiology of gastroenteric viruses in hospitalized children are particularly important to evaluate the impact of the rotavirus vaccine in Brazil.

Genotypes and molecular epidemiology of human astroviruses in hospitalized children with acute gastroenteritis in Rio de Janeiro, Brazil

Human astrovirus (HAstV) is an important pathogen that causes acute gastroenteritis mainly in children up to 5 years old worldwide. A total of 318 fecal samples were collected from January to December of 2004 from children with acute gastroenteritis hospitalized in Rio de Janeiro (RJ), Brazil. The samples were obtained from three public hospitals and were previously investigated for the presence of rotavirus (RV) and enteric adenovirus (AdV). The aim of this study was to determine the prevalence and molecular characterization of HAstV by reverse-transcription polymerase chain reaction (RT-PCR) and partial sequencing of open reading frame 2 (ORF2). HAstV infections were detected in 43 (14%) of the samples, of which 19 (6%) were mixed infections with HAstV and RV. HAstV were identified in all age groups, with 85% of the cases occurring in children younger than 2 years old. HAstV infections were more prevalent from March to May. Diarrhea, vomiting, and fever were the main clinical manifestations observed in these infections. Partial capsid sequencing of 35 HAstV strains characterized 25 (71%) as genotype 1 (HAstV-1), 6 (17%) HAstV-2, 3 (9%) HAstV-8, and 1 (3%) HAstV-4. Based on the genetic variability, three lineages were observed between RJ HAstV-1 strains. This study demonstrated the importance of HAstV infections causing acute infantile gastroenteritis in hospitalized children in RJ, Brazil. Molecular epidemiological surveillance is helpful for designing prevention strategies of HAstV transmission.