RESUMO
BACKGROUND: Between September 2000 and November 2005, approximately 10% of the retrospectively examined human adenovirus (HAdV)-positive pediatric cases of acute respiratory disease (ARD) requiring hospitalization at the Hospital Nacional de Pediatria Juan P. Garrahan in Buenos Aires, Argentina, were found to have a HAdV-B2 infection. OBJECTIVE: To characterize genetically and antigenically the HAdV-B2 virus isolates. STUDY DESIGN: Restriction enzyme analysis (REA), hexon and fiber gene sequencing and virus neutralization assays (VN) were carried out on 8 HAdV-B2 respiratory virus isolates. RESULTS: REA showed that the 8 examined HAdV-B2 virus isolates were HAdV11, belonging to two genomic variants: HAdV11a and a BclI variant of HAdV11c which we designated 11c4. Molecular analysis of the hexon genes showed that both REA variants had a HAdV11-like hexon gene. Confirming previous reports, the 7 HAdV11a virus isolates were found to have HAdV14-like fiber genes and therefore are HAdV H11/F14. The fiber gene of the HAdV11c4 virus isolates most closely resembled that of various strains of HAdV7. In VN assays, the 4 tested HAdV11a strains were serotyped as HAdV11-14. The HAdV11c4 strain was serotyped as HAdV11 but also showed a weak but significant reactivity with antiserum to HAdV7. Compared with the other HAdV-positive cases in our study, infection with HAdV11 caused a similarly severe disease. CONCLUSIONS: Our results provide evidence to the long term world-wide circulation of HAdV H11/F14 as a causative agent of ARD. Combined, our molecular and serology data support the rationale to base the molecular typing and designation of recombinant viruses on the sequences of the hexon and fiber genes.
Assuntos
Infecções por Adenoviridae/virologia , Adenovírus Humanos/classificação , Doenças Respiratórias/virologia , Adenovírus Humanos/genética , Adenovírus Humanos/imunologia , Adenovírus Humanos/isolamento & purificação , Argentina , Criança , Pré-Escolar , DNA Viral/química , DNA Viral/genética , Feminino , Genótipo , Humanos , Lactente , Masculino , Epidemiologia Molecular , Dados de Sequência Molecular , Testes de Neutralização , Polimorfismo de Fragmento de Restrição , Proibitinas , Análise de Sequência de DNA , SorotipagemRESUMO
Antigenic and genetic analysis of the hemagglutinin of approximately 13,000 human influenza A (H3N2) viruses from six continents during 2002-2007 revealed that there was continuous circulation in east and Southeast Asia (E-SE Asia) via a region-wide network of temporally overlapping epidemics and that epidemics in the temperate regions were seeded from this network each year. Seed strains generally first reached Oceania, North America, and Europe, and later South America. This evidence suggests that once A (H3N2) viruses leave E-SE Asia, they are unlikely to contribute to long-term viral evolution. If the trends observed during this period are an accurate representation of overall patterns of spread, then the antigenic characteristics of A (H3N2) viruses outside E-SE Asia may be forecast each year based on surveillance within E-SE Asia, with consequent improvements to vaccine strain selection.