RESUMO
Group A rotaviruses (RVA) are the most frequent etiological agents causing severe diarrhea in infants and surveillance of genotype, and genetic characteristics of circulating strains are necessary in order to evaluate vaccine programs. The objectives of this work were to describe G and P genotype from 2012 through 2014 in Buenos Aires, Argentina completing an overview of 19 years of genotype surveillance in our region and to characterize an emerging G1P[8] strain associated with severe cases and five fatalities in 2014. We performed genotyping by RT-PCR. The sequencing of several genes, phylogenetic analyses, and comparative epidemiological data were used to know the origin and phylogenetic relationships of the emerging G1P[8] strain. Along with this report, 19 years of continuous RVA genotype surveillance in Argentina in the pre-vaccine era was covered. During the last year of this surveillance, 2014, a significantly increased incidence of RVA associated gastroenteritis was related to the reemergence of G1P[8] strains, being these ones detected in low frequency in the last nine years. Interestingly, the patients affected were significantly older when compared with those from the last six seasons. Additionally, phylogenetic analysis of several genes infer that these G1P[8] strains were closely related to Asian strains circulating during 2012 and 2013. In addition to this, the suggested extra continental origin for the 2014 G1P[8] strains and the very low circulation of G1 type during nine years probably explain the increased incidence and severity in the gastroenteritis cases and the particular epidemiologic characteristics. In conclusion, this work gives us a whole panorama of the pre-vaccine era of the RVA molecular epidemiology in the most populated region of Argentina. In this way, this work inspires us to continue with this type of studies in the post-vaccination era.
Assuntos
Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Rotavirus/classificação , Argentina/epidemiologia , Proteínas do Capsídeo/genética , Doenças Transmissíveis Emergentes/história , Genoma Viral , Genótipo , História do Século XXI , Humanos , Incidência , Epidemiologia Molecular , Filogenia , Prevalência , Vigilância em Saúde Pública , RNA Viral , Rotavirus/imunologia , Infecções por Rotavirus/história , Infecções por Rotavirus/prevenção & controle , Vacinas contra RotavirusRESUMO
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.
Assuntos
Genes Virais , Vírus Reordenados/genética , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Rotavirus/classificação , Rotavirus/genética , Brasil/epidemiologia , Genoma Viral , Genômica/métodos , História do Século XXI , Humanos , Filogenia , Vigilância em Saúde Pública , RNA Viral , Infecções por Rotavirus/históriaRESUMO
BACKGROUND: Group A rotaviruses (RVA) are the most frequent single etiological agents of severe diarrhea in infants. Since 2006 RVA vaccines have been introduced in national schedules of middle and high income countries with substantial declines in rotavirus associated disease burden. However, surveillance must be maintained to, eventually, detect emerging types or variants selected by the new pressure imposed by vaccination. OBJECTIVES: To analyze the molecular epidemiology of group A rotavirus after vaccine introduction in the region in the context of data from more than 15 years of continuous surveillance in Buenos Aires. STUDY DESIGN: RVA positive diarrhea samples collected in Buenos Aires from 2008 to 2011 were genotyped by RT-PCR. Selected samples were sequenced to gain insight on evolution of common and globally emerging human RVA strains. RESULTS: Lineage III G12P[8] strain emerged in 2008 in Buenos Aires and shared co-dominancy with G3 strains during 2009. An atypical long lasting circulation of G2P[4] strains since 2004 reached rates around 80% in 2011 in Buenos Aires. Sequencing of the VP7 and VP4 genes of representative G2P[4] isolates suggests Brazil as the origin of the 2010-2011 strains. CONCLUSIONS: Globally emergent G12 lineage III strains could be established as dominant strains in a very populated area in two years since emergence. In this work it was also shown that the persistence of G2P[4] strains during 8 years could be related to massive immunization with the monovalent vaccine in the region.