Detection of a novel species A, DS-1-like, G4P[6] rotavirus strain from a Brazilian child with gastroenteritis.

Rotaviruses belonging to species A (RVA) remain among the most common causes of severe gastroenteritis in children aged <5 years, leading to substantial morbidity and mortality worldwide. Genome reassortment events between two human strains or human and animal strains represent one of the mechanisms which appear to generate the broad genetic variability of circulating. According to a nucleotide, sequence-based classification system, RVA strains are currently classified into three genotype constellations including Wa-like (genogroup I), DS-1-like (genogroup II), and AU-like (genogroup III). The present study reports the detection of an unusual RVA G4P[6] strain (coded as strain HSE005), which might have originated from a natural reassortment event between human and animal RVA strains. Molecular characterization of this isolate showed that it belonged to genogroup II, genotype G4P[6]. In addition, two genes (VP3 and NSP4) of this strain denoted evidence of reassortment events involving strains of distinct zoonotic evolutionary origins. Therefore, we propose that a new G4P[6] strain was identified, highlighting a possible first zoonotic transmission including a reassortment event that involved the VP3 gene.

Prevalence of rotavirus and human bocavirus in immunosuppressed individuals after renal transplantation in the Northern Region of Brazil.

Immunosuppressive therapy causes severe impairment of host defense and diarrhea is a frequent complication in renal transplant recipients. This study aimed to describe the occurrence of Rotavirus A (RVA) and Human Bocavirus (HBoV) in fecal samples of immunosuppressed patients submitted to renal transplantation during posttransplant follow-up. A longitudinal study was carried out involving a 25-patient cohort, selected for kidney transplantation. A total of 126 fecal samples were collected between May 2014 and May 2016. Molecular techniques were used to detect and characterize circulating RVA and HBoV genotypes and statistical analysis were applied to verify the association between epidemiological and clinical characteristics. The prevalence of RVA and HBoV was 24% (6/25) and 40% (10/25), respectively. Among RVA and HBoV positive cases, the majority was female; did not conduct water treatment nor had adequate sewage facilities. The most detected genotypes were RVA G3 (62.5%) and HBoV-3 (95%). Phylogenetic analysis of HBoV strains indicated that studied samples were similar to those found in Asian and American countries. The present study point out the circulation of these viral agents among immunosuppressed individuals and these findings will enable the construction of new knowledge and care perspectives on the cause of diarrhea in this population.

Emergence of G12P[6] rotavirus strains among hospitalised children with acute gastroenteritis in Belém, Northern Brazil, following introduction of a rotavirus vaccine.

Species A rotavirus still remains a major cause of acute gastroenteritis in infants and young children. Globally, six genotypes (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]) account for >90% of circulating strains; however, genotype G12 in combination with P[6] or P[9] has been detected at increasing rates. We sought to broaden our knowledge about the rotavirus strains circulating during the early post-vaccine-introduction period. Stool samples were obtained from children hospitalised for acute gastroenteritis in Belém, Northern Brazil, from May 2008 to May 2011 and examined by reverse transcription polymerase chain reaction and nucleotide sequencing. A total of 122 out of the original 1076 rotavirus strains were judged to be non-typeable in the first analysis and were therefore re-examined. G2P[4] was the most prevalent genotype (58.0%), followed by G1P[8] (16.9%), and G12P[6] (7.5%). G12P[6] strains were identified at similar rates during the first (2.5%) and second (3.9%) years, and the rate jumped to 15.6% in the third year. Analysis of VP7 sequences of the G12P[6] strains showed that they belonged to lineage III. In addition, co-circulating G12P[6] strains displaying long and short RNA patterns were found to belong to the Wa-like and DS-1-like constellation, respectively. Additional unusual circulating strains G12P[9] and G3P[9] were also identified. This hospital-based study showed a high prevalence of G12P[6] strains in the third year of surveillance. Our results highlight the need for continuous longitudinal monitoring of circulating rotavirus strains after introduction of rotavirus vaccines in Brazil and elsewhere.

Rotavirus antigenemia as a common event among children hospitalised for severe, acute gastroenteritis in Belém, northern Brazil.

BACKGROUND: Rotavirus antigenemia and RNAemia (the presence of rotavirus RNA in serum) have been commonly identified among paediatric patients with acute gastroenteritis. In this study we examined the association between rotavirus antigenemia and clinical features, and sought to determine the genotypes of rotaviruses detected in paired stool and serum samples. METHODS: Paired stool and serum samples were obtained from children hospitalised for acute gastroenteritis in Belém, Brazil, between June 2012 and June 2015. The 20-point Vesikari scoring system was used to assess the disease severity upon a retrospective medical record review. Stool and serum samples were primarily screened for the presence of rotavirus antigen using a commercial ELISA assay. The rotavirus isolates from stool and serum samples were genotyped by using the classical reverse-transcriptase polymerase chain reaction (RT-PCR) and/or through nucleotide sequencing of VP4 and VP7 genes. Viral load was estimated using real-time RT-PCR. RESULTS: In total rotavirus antigen was detected in 109 (24.2%) stool samples from 451 children, whereas antigenemia occurred in 38.5% (42/109) of these patients. We demonstrated that patients positive for rotavirus RNA in paired stool and serum samples were more likely to have a higher frequency of vomiting episodes in a 24-h period (p = 0.0035). Our findings also suggested that children not vaccinated against rotavirus are more likely to develop antigenemia, as compared to those given at least one vaccine dose (p = 0.0151). G12P [8] and G2P [4] genotypes were predominant throughout the study period, accounting for 52.3% (57/109) and 27.5% (30/109) of the typed isolates, respectively. Ten stool-serum pairs could be typed for VP4 and VP7 genes. Seven of these pairs showed concordant results with G2P [4] genotype being detected in stool and serum samples, whereas discrepancies between genotypes (G2P [4]/G2P[NT] and G12P [8]/G2P[NT]) were seen in three pairs. CONCLUSIONS: Rotavirus antigenemia and RNAemia occur in a significant number of children hospitalised for acute gastroenteritis in Belém, Brazil, and may contribute to a greater disease severity, particularly translated into a greater number of vomiting episodes. This study documented a high concordance of genotypes detected in a subgroup of paired stool and serum samples.

Analysis of a genotype G3P[9] rotavirus a strain that shows evidence of multiple reassortment events between animal and human rotaviruses.

The species A rotaviruses (RVA) are important gastroenteric pathogens that infect humans and animals. RVA genotype G3P[9] has been described in human-animal reassortment events, and the complexity of its hosts motivates the genetic investigation of this strain. Therefore, the aim of this study is to analyse a G3P[9] sample that was detected in a child with acute gastroenteritis. The 1A3739 sample featured the constellation G3P[9]-I18-R3-C3-Mx-A19-N3-T3-E3-H6. The sequence for VP3 gene was not obtained. The phylogeny showed a closer relationship among genes VP7, VP1, NSP3, NSP4, and NSP5 with genes of animal origin, such as chiropter, alpaca, equine, and simian. In addition, the genes VP6 and NSP1 belong to the new genotypes I18 and A19, respectively. The emergence of strains such as these can interfere with the effectiveness of the RVA vaccine, and continuous monitoring is therefore important. Additional studies are needed to determine the evolutionary source and to identify a possible reservoir of RVA in nature.

Norovirus genogroups I and II in environmental water samples from Belém city, Northern Brazil.

This study investigated the presence of norovirus (NoV) GI and GII in environmental samples from the northern region of Brazil. Water samples were collected monthly (November 2008/October 2010) from different sources and sewage and concentrated by the adsorption-elution method. The NoV investigation used molecular methods followed by sequencing reactions. The general positivity for NoV was 33.9% (57/168). Considering the results obtained only in the semi-nested RT-PCR (reverse transcription polymerase chain reaction) and only in the TaqMan® real-time PCR, the rates were 26.8% (45/168) and 27.4% (46/168), respectively, being for NoV GI 22.2% (10/45) and 19.6% (9/46); for GII 17.8% (8/45) and 15.2% (7/46); and for GI + GII 60% (27/45) and 65.2% (30/46), respectively. Different GI (GI.1, GI.4, GI.7 and GI.8) and GII (GII.4, GII.6, GII.9, GII.12 and GII.14) genotypes were detected. These results demonstrated the NoV was disseminated in the waters of Belém city due to a lack of sanitation that allowed the discharge of contaminated effluents into these aquatic ecosystems.

High prevalence of norovirus in children with sporadic acute gastroenteritis in Manaus, Amazon Region, northern Brazil.

BACKGROUND: Norovirus (NoV) is a major cause of acute gastroenteritis (AGE) worldwide, especially in children under five years. Studies involving the detection and molecular characterisation of NoV have been performed in Brazil, demonstrating its importance as an etiological agent of AGE. OBJECTIVES: The objectives of this study were to investigate the frequency of human NoV and to genotype the strains isolated from 0-14-year-old patients of AGE in Manaus, Brazil, over a period of two years. METHODS: A total of 426 faecal samples were collected between January 2010 and December 2011. All samples were tested for the presence of NoV antigens using a commercial enzyme immunoassay kit. RNA was extracted from all faecal suspensions and reverse transcription-polymerase chain reaction (RT-PCR) for the NoV-polymerase partial region was performed as a trial test. Positive samples were then subjected to PCR with specific primers for partial capsid genes, which were then sequenced. FINDINGS: NoV was detected in 150 (35.2%) faecal samples, for at least one of the two techniques used. NoV was detected in children from all age groups, with the highest positivity observed among the group of 1-2 years old. Clinically, fever was verified in 43% of the positive cases and 46.3% of the negative cases, and vomiting was observed in 75.8% and 70.8% cases in these groups, respectively. Monthly distribution showed that the highest positivity was observed in January 2010 (81.2%), followed by February and April 2010 and March 2011, when the positivity rate reached almost 50%. Phylogenetic analyses performed with 65 positive strains demonstrated that 58 (89.2%) cases of NoV belonged to genotype GII.4, five (7.7%) to GII.6, and one (1.5%) each to GII.7 and GII.3. MAIN CONCLUSIONS: This research revealed a high circulation of NoV GII.4 in Manaus and contributed to the understanding of the importance of this virus in the aetiology of AGE cases, especially in a region with such few studies available.

Detection of a novel equine-like G3 rotavirus associated with acute gastroenteritis in Brazil.

Genotype G3P[8] of rotavirus A (RVA) is detected worldwide, usually associated with Wa-like constellation and exhibiting a long RNA migration pattern. More recently, a novel inter-genogroup, G3P[8] reassortant variant with a short electropherotype, has emerged in Asia, Oceania and Europe, denoting an overall potential of unusual rotavirus strains. During a RVA surveillance in Brazil, G3P[8] strains were found displaying a short electropherotype pattern, which had not been detected before in this region. This study aims to characterize the complete genome of 10 G3P[8] strains detected in the northern region of Brazil. All G3P[8] samples were subjected to partial sequencing, and the whole-genome phylogenetic analysis demonstrated that all strains possessed I2-R2-C2-M2-A2-N1-T2-E2-H2 genotype background, representing reassortants with an equine-like G3 VP7 and amino acid changes in VP4 and VP7 antigenic regions as compared to vaccine strains. Phylogenetic analysis demonstrated high nucleotide identity in almost all RNA segments of G3P[8] DS-1 samples detected in Asia, Oceania and Europe as well as G3P[4] strains in Japan. This study reports a novel, equine-like G3P[8] strain circulating in Brazil and isolated from children hospitalized for severe gastroenteritis, and highlights the complex dynamics of RVA molecular epidemiology. Our findings point to a novel RVA strain emerging in this region, and studies should be done to detect whether this may represent a challenge to current vaccine strategies.

Phylogenetic analysis of human group C rotavirus in hospitalized children with gastroenteritis in Belém, Brazil.

Group C rotavirus (RVC) is potentially an important pathogen associated with acute gastroenteritis (AG), especially in outbreaks. This study aims to detect and molecularly characterize RVC in hospitalized children with AG in Belém, Brazil. From May 2008 to April 2011, 279 stools were subjected to reverse-transcription polymerase chain reaction targeting VP7, VP6, VP4, and NSP4 genes. RVC positivity rate was 2.1% (6/279) and phylogenetic analysis of positive samples yields genotype G4-P[2]-I2-E2. No evidence of zoonotic transmission and VP7 gene demonstrated close relationship with Asian strains. RVC surveillance is worth to expand information on evolutionary and epidemiological features of this virus.

High prevalence of G12P[8] rotavirus strains in Rio Branco, Acre, Western Amazon, in the post-rotavirus vaccine introduction period.

The present study aimed to provide a molecular characterization of circulating rotavirus (RVA) strains in Rio Branco, Acre, in the post-rotavirus vaccination period, particularly with regard to the emerging, increasingly prevalent G12P[8] genotype. A total of 488 fecal specimens from diarrheic and non-diarrheic children were obtained between January and December 2012. RVA detection was initially performed using enzyme-linked immunosorbent assay (ELISA) method, followed by reverse-transcription polymerase chain reaction (RT-PCR) using specific primers. RVA was detected in 18.3% (44/241) of the children with acute diarrhea and in 1.2% (3/247) of the non-diarrheic children (P < 0.001), with overall RVA-positivity of 9.6% (47/488). The most common genotype was G2P[4] with 43.2% (19/44) of the diarrheic cases, followed by G12P[8] (27.3%, 12/44), G3P[6] (18.2%, 8/44), G3P[8] (4.5%, 2/44), and G12P[6] (2.3%, 1/44). G12 samples belonged to lineage III and were from children aged 4-52 months. All of these children had acute diarrhea associated with fever (83.3%, 10/12) and vomiting (66.7%, 8/12). Most of the cases occurred in August (58.3%, 7/12), 75% (9/12) of which having received the full vaccination scheme with Rotarix™. For the first time G12 was reported at relative high prevalence in Brazil. Our findings warrant further monitoring studies on the molecular characterization of circulating RVA strains after rotavirus vaccine introduction in Brazil and elsewhere, since the occurrence of either unusual our emerging genotypes may pose a challenge to vaccination strategies.

Detection of the VP6 gene of group F and G rotaviruses in broiler chicken fecal samples from the Amazon region of Brazil.

The aim of this study was to detect rotavirus F (RVF) and rotavirus G (RVG) in fecal specimens of broiler chickens in Brazil. During 2008 and 2011, a total of 85 fecal samples were collected. The viral genome was extracted, followed by polyacrylamide gel electrophoresis (PAGE), reverse transcription polymerase chain reaction (RT-PCR), and nucleotide sequencing. Samples were screened for rotaviruses by PAGE, and RVF and RVG genome banding patterns were not seen. Using RT-PCR, it was found that 9.4 % (8/85) of the pools contained RVF, whereas 10.6 % (9/85) contained RVG. The predicted amino acid sequences of RVF and RVG from Brazilian samples were 94.4-95.7 % and 96.8-96.9 % identical, respectively, to those of prototypes from Germany. The detection of RVF and RVG in this study provides important epidemiological data about the simultaneous circulation of rotaviruses affecting broiler flocks in the Amazon region of Brazil.

Clinical Severity and Rotavirus Vaccination among Children Hospitalized for Acute Gastroenteritis in Belém, Northern Brazil.

In March 2006, Brazil introduced the monovalent rotavirus (RV) vaccine (Rotarix™) into the public sector. This study assessed the severity of rotavirus gastroenteritis (RVGE) according to the vaccination status among hospitalized children. We identified 1023 RVGE episodes among not vaccinated (n = 252), partially vaccinated (n = 156) and fully vaccinated (n = 615) children. Very severe gastroenteritis (scored ≥ 15) was reported in 16.7, 17.9 and 13.5% of not vaccinated, partially vaccinated and fully vaccinated children, respectively. There was a trend for a shorter duration of RV diarrhoea among vaccinated children than in not vaccinated children (p = 0.07). A protective effect of vaccination was noted when mean duration of symptoms and hospital stay are analysed, comparing unvaccinated, partially vaccinated and fully vaccinated children (p < 0.05). We showed a vaccination dose effect trend, with fully vaccinated children having less-severe RVGE than not vaccinated and partially vaccinated children.

Rotavirus strain surveillance for three years following the introduction of rotavirus vaccine into Belém, Brazil.

The monovalent human rotavirus (RV) vaccine, RIX4414 (Rotarix™, GlaxoSmithKline Biologicals) was introduced into Brazil's Expanded Program on Immunization in March 2006. One year after vaccine introduction, the G2P[4] strain was found to be predominant, with an apparent extinction of many non-G2 strains. This study investigated the diversity of circulating strains in the three years following RIX4414 introduction. Between May 2008 and May 2011, stool samples were collected from children aged ≥12 weeks who were hospitalized for severe lab confirmed RV-gastroenteritis (≥3 liquid or semi-liquid motions over a 24-h period for <14 days, requiring ≥1 overnight hospital stay and intravenous rehydration therapy) in Belém, Brazil. RV-gastroenteritis was detected by ELISA and the G- and P-types were determined by RT-PCR assays. During the first year of surveillance nucleotide sequencing was used for typing those samples not previously typed by RT-PCR. A total of 1,726 of 10,030 severe gastroentertis hospitalizations (17.2%) were due to severe RVGE. G2P[4] was detected in 57.2% of circulating strains over the whole study period, however it predominated during the first 20 months from May 2008 to January 2009. G1P[8] increased in the last part of the study period from May 2010 to May 2011 and represented 36.6% (112/306) of the circulating strains. G2P[4] was the predominant RV strain circulating during the first 20 months of the study, followed by G1P[8]. These findings probably reflect a natural fluctuation in RV strains over time, rather than a vaccine-induced selective pressure.

Genogroup I avian picobirnavirus detected in Brazilian broiler chickens: a molecular epidemiology study.

Picobirnavirus (PBV) belongs to the family Picobirnaviridae. Picobirnaviruses contain a bisegmented dsRNA genome that is non-enveloped. A total of 85 pooled faecal samples were collected from the poultry of 37 farms from the Metropolitan Mesoregion of Belém (MMB), Pará state, Brazil. The viral RNA from each sample was analysed by PAGE and reverse transcriptase PCR (RT-PCR). For each county affected, at least one positive sample was selected, cloned and sequenced. The samples showed a positivity of 15.3 % (13/85) by PAGE and 49.4 % (42/85) by RT-PCR. Sequencing of these strains demonstrated a considerable RdRp gene heterogeneity that ranged from 56.1 to 100 % at the nucleotide level compared with prototypes of different species and water sewage, and from 50.3 to 100 % among themselves. Avian picobirnavirus (AvPBV) was detected in MMB broiler farms and showed a heterogeneous relationship with the prototypes used. This report includes what is believed to be the first gene sequencing of AvPBV in Brazilian broiler chickens.

Diversity of rotavirus strains circulating in Northern Brazil after introduction of a rotavirus vaccine: high prevalence of G3P[6] genotype.

Rotavirus A (RVA) is the most common cause of severe acute gastroenteritis in infants and young children worldwide, causing 453,000 deaths annually. In Brazil, the most frequent genotype identified was G1 during almost three decades in the pre-vaccination period; however, after anti-rotavirus vaccine introduction, there was a predominance of G2 genotype. The aim of this study was to determine the G and P genotypes of rotaviruses isolated from children under 5 years of age with acute gastroenteritis in the Northern region of Brazil, and discuss the emergence of G3P[6] genotype. A total of 783 stool specimens were obtained between January 2011 and March 2012. RVA antigen was detected in 33% (272/783) of samples using a commercial enzyme-linked immunosorbent assay and type-specificity was determined by reverse-transcription polymerase chain reaction. The most common binary combination was G2P[4], representing 41% of cases, followed by G3P[6] (15%), G1P[8] (8%), G3P[8] (4%), G9P[8] (3%), and G12P[6] (2%). G3P[6] strains were analyzed further and phylogenetic analysis of VP7 gene showed that G3 strains clustered into lineage I and showed a high degree of amino acid identity with vaccine strain RV3 (95.1-95.6%). For VP4 sequences, G3P[6] clustered into lineage Ia. It was demonstrated by the first time the emergence of unusual genotype G3P[6] in the Amazon region of Brazil. This genotype shares neither VP7 nor VP4 specificity with the used vaccine and may represent a challenge to vaccination strategies. A continuous monitoring of circulating strains is therefore needed during the post-vaccine era in Brazil.

Genetic diversity of porcine sapoviruses in pigs from the Amazon region of Brazil.

Sapoviruses (SaVs) belong to the family Caliciviridae and are related to gastroenteritis viruses of humans and animals. These agents have been reported from several countries of the world and represent an important cause of economic loss. The Amazon area has a high degree of diversity of animals and plants, is located in the Northern Region of Brazil and accounts for a large part of the Brazilian territory. In this study, stool samples were collected from pigs during the phase of nursing (less than 28 days of age) and post-weaning (29 to 56 days of age) from January 2008 to February 2009. A total of 169 specimens (108 nursing and 61 post-weaning pigs) were tested by reverse transcription polymerase chain reaction (RT-PCR) using the primers p289/p290 for the detection of caliciviruses (CVs), i.e., SaVs and noroviruses (NoVs). Positive sequences were analyzed using BioEdit software (v. 7.1.3.0) and compared with other sequences registered in the GenBank database. A positive frequency of 12.4 % (21/169) was observed, and all of the viruses found were identified as SaVs, with 15 belonging to genogroup GIII (71.4 %), three to GVII-1 (14.3 %) and three to GVIII-2 (14.3 %). No NoVs were detected. The frequency of SaV infections was significantly higher in nursing pigs (17.6 %-19/108) than in post-weaning pigs (3.3 %-2/61). Considering the consistency of the samples, 14.7 % of the samples were classified as diarrheic, but statistical analysis demonstrated that there was no significant difference compared to normal specimens (p = 0.5795). For the first time, we have demonstrated the circulation of SaVs in pigs from the Amazon.

Detection, epidemiology and characterization of VP6 and VP7 genes of group D rotavirus in broiler chickens.

Rotaviruses infect humans and animals and are classified into eight groups (A to H). Group D rotavirus (RVD) has been described in birds, although relatively few reports are available. The present study focused on RVD, including epidemiological and molecular aspects of samples collected from broiler chickens in the state of Pará, Brazil. A total of 85 faecal samples were collected between 2008 and 2011 from 37 chicken farms located in eight different municipalities. The viral double-stranded RNA was extracted from faecal suspensions and analysed using polyacrylamide gel electrophoresis (PAGE), followed by reverse transcriptase-polymerase chain reaction (RT-PCR) and nucleotide sequencing of the VP6 and VP7 genes. Comparing the positive results, 16.5% (14/85) were obtained by PAGE and 35.3% (30/85) by RT-PCR. Samples from seven of eight municipalities were positive for RVD and infections were recorded in 17 (45.9%) of 37 chicken farms. The RVD infection rate was significantly higher in the 16-day to 30-day age group (62.2%; 23/37) compared with other ages. No consistent relationship was found between the infection rate and either the population density in poultry houses or the climatic conditions. The nucleotide sequences of the VP6 gene were 89.9 to 90.9% similar to the prototype strain 05V0049 and were 88.3 to 100% similar among themselves; VP7 gene nucleotide sequences were 84.3 to 85.4% similar to the prototype strain 05V0049 and 93.8 to 100% similar among themselves. Overall, this study provides new insights into the epidemiology and genome characterization of group D rotaviruses.

Norovirus infection in children admitted to hospital for acute gastroenteritis in Belém, Pará, Northern Brazil.

Noroviruses are the leading cause of epidemic, non-bacterial outbreaks of acute gastroenteritis, and are also a major cause of sporadic acute gastroenteritis in infants. The aim of the present study was to identify norovirus infections in children not infected by rotavirus admitted to hospital for acute gastroenteritis in Belém. A total of 348 fecal specimens were obtained from children with diarrhea aged less than 5 years, all of whom had tested negative for rotavirus, between May 2008 and April 2010. Fecal samples were screened for norovirus antigen using enzyme-immunoassay (EIA). Specimens were subjected to reverse-transcription polymerase chain reaction (RT-PCR) using the primers Mon432/434-Mon431/433 for detection of the GI and GII norovirus strains, respectively. Based on both methods, the overall norovirus positivity rate was 36.5% (127/348). Of the 169 samples collected in the first year, 44.4% (n = 75) tested positive for norovirus using both methods, 35.5% (n = 60) by EIA and 40.8% (n = 69) by RT-PCR. Using RT-PCR as a reference standard, a sensitivity of 78.3%, specificity of 94%, and agreement of 87.6% were recorded. Genome sequencing was obtained for 22 (31.9%) of the 69 positive samples, of which 90.9% (20/22) were genotype GII.4d and 9.1% (2/22) were genotype GII.b. Norovirus infection was most frequent in children under 2 years of age (41.5%-115/277). The peak incidence (62.1%) of norovirus-related acute gastroenteritis in these patients (not infected by rotavirus) was observed in February 2010. These findings emphasize the importance of norovirus as a cause of severe acute gastroenteritis among children in Belém, Pará, Northern Brazil.

Detection of the pandemic norovirus variant GII.4 Sydney 2012 in Rio Branco, state of Acre, northern Brazil.

Noroviruses (NoVs) are important cause of gastroenteritis in humans worldwide. Genotype GII.4 is responsible for the majority of outbreaks reported to date. This study describes, for the first time in Brazil, the circulation of NoV GII.4 variant Sydney 2012 in faecal samples collected from children aged less than or equal to eight years in Rio Branco, state of Acre, northern Brazil, during July-September 2012.

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

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