Molecular characterization of astrovirus in stool samples from children in São Paulo, Brazil

The purpose of this study was to characterize astrovirus in faecal samples collected from children with and without diarrhea in São Paulo, Brazil, grouped into two sets: EPM and HU. Detection and genotyping were carried out using reverse transcription nested polymerase chain reaction (RT-PCR) with specific primers directed towards the genome open reading frame 2 (ORF2). Results for EPM set showed that 66/234 (28.2%) were positive: 28/94 (29.7%) from children with acute diarrhea, 14/45 (31.1%) with persistent diarrhea, and 9/55 (16.3%) from control individuals. No data was available for 15/40 (37.5%) of samples. Mixed infections with other viruses were found in 33 samples. In the HU, 18/187 (9.6%) were positive: 12/158 (7.6%) from individuals with acute diarrhea and 6/29 (20.7%) from control children. Four samples were mixed with other viruses. Out of 66 astrovirus positive EPM samples, 18 (27.2%) were characterized as human astrovirus type-1 (HAstV-1), two (3.0%) as HAstV-2, two (3.0%) as HAstV-3, and three (4.5%) as HAstV-8. Among 18 astrovirus positive HU samples, one (5.5%) was characterized as HAstV-1, six (33.3%) as HAstV-2, and one (5.5%) as HAstV-8. Two HAstV-8 genotyped samples were further confirmed by nucleotide sequencing. Our results shows that astroviruses are circulating in a constant manner in the population, with multiple serotypes, in higher frequency than it was described for other Brazilian regions. For the first time in Sao Paulo, Brazil, it was shown that astroviruses play an important role in children gastroenteritis, as described for most locations where they were detected

Detection, Subgroup Specificity, and Genotype Diversity of Rotavirus Strains in Children with Acute Diarrhea in Paraguay

Of a total of 220 stool specimens from children with acute diarrhea, mostly under the age of 3 years, collected in Paraguay between January 1999 and March 2000, 70 (31.8%) were found positive for rotaviruses (RV). Positive samples were characterized by electropherotyping and subgrouping. Sixty-one (87.1%) were classified as group A, subgroup II; one (1.4%) was classified as group A, subgroup I; six (8.6%) were group A, non-I non-II; and two (2.9%) were not tested. RV strains were G and P genotyped by reverse transcription-PCR. The following G types were detected: G4 (34.3%), G1 (21.4%), G2 (1.4%), and G9 (5.7%). Mixtures of human and animal genotypes were detected in 15 (21.4%) samples, and 11 samples (15.7%) were nontypeable. The following P types were detected: P[8] (48.6%), P[4] (1.4%), and P[1] (1.4%). A mixed type was found in 10% of samples, and an unexpectedly high percentage (38.6%) of nontypeable samples was found. The common human G- and P-type combinations P[8], G4 (15.7%) and P[8], G1 (14.2%) were detected. Mixed human and animal genotypes were observed as the following combinations: G4 + G5, G4 + G5 + G10, and G1 + G10 for G types and P[8]-P[1] for P types. The emerging G9 genotype was detected in four samples. These results show for the first time the diversity of RV circulating among children in Paraguay and contribute to the knowledge of this pathogen required to devise strategies to prevent diarrheal illness in this country. The finding of mixed genotypes may indicate interspecies transmission of RV between humans and animals.

Projecting the effectiveness of RotaTeq® against rotavirus-related hospitalisations in Brazil

RotaTeq® (Merck & Company, Inc, Whitehouse Station, NJ, USA) is an oral pentavalent rotavirus vaccine (RV5) that has shown high and consistent efficacy in preventing rotavirus gastroenteritis (RGE) in randomised clinical trials previously conducted in industrialised countries with high medical care resources. To date, the efficacy and effectiveness data for RV5 are available in some Latin American countries, but not Brazil. In this analysis, we projected the effectiveness of RV5 in terms of the percentage reduction in RGE-related hospitalisations among children less than five years of age in four regions of Brazil, using a previously validated mathematical model. The model inputs included hospital-based rotavirus surveillance data from Goiânia, Porto Alegre, Salvador and São Paulo from 2005-2006, which provided the proportions of rotavirus attributable to serotypes G1, G2, G3, G4 and G9, and published rotavirus serotype-specific efficacy from the Rotavirus Efficacy and Safety Trial. The model projected an overall percentage reduction of 93% in RGE-related hospitalisations, with an estimated annual reduction in RGE-related hospitalisations between 42,991-77,383 in the four combined regions of Brazil. These results suggest that RV5 could substantially prevent RGE-related hospitalisations in Brazil

Molecular Characterisation Of The Nsp4 Gene Of Group A Human Rotavirus G2p[4] Strains Circulating In São Paulo, Brazil, From 1994 And 2006 To 2010.

Group A human rotaviruses (HuRVA) are causative agents of acute gastroenteritis. Six viral structural proteins (VPs) and six nonstructural proteins (NSPs) are produced in RV-infected cells. NSP4 is a diarrhoea-inducing viral enterotoxin and NSP4 gene analysis revealed at least 15 (E1-E15) genotypes. This study analysed the NSP4 genetic diversity of HuRVA G2P[4] strains collected in the state of São Paulo (SP) from 1994 and 2006-2010 using reverse transcription-polymerase chain reaction, sequencing and phylogenetic analysis. Forty (97.6%) G2P[4] strains displayed genotype E2; one strain (2.4%) displayed genotype E1. These results are consistent with the proposed linkage between VP4/VP7 (G2P[4]) and the NSP4 (E2) genotype of HuRVA. NSP4 phylogenetic analysis showed distinct clusters, with grouping of most strains by their genotype and collection year, and most strains from SP were clustered together with strains from other Brazilian states. A deduced amino acid sequence alignment for E2 showed many variations in the C-terminal region, including the VP4-binding domain. Considering the ability of NSP4 to generate host immunity, monitoring NSP4 variations, along with those in the VP4 or VP7 protein, is important for evaluating the circulation and pathogenesis of RV. Finally, the presence of one G2P[4]E1 strain reinforces the idea that new genotype combinations emerge through reassortment and independent segregation.110786-79