Abstract

Respiratory infections are the most important cause of worldwide burden of disease in children and a major cause of mortality. In this study, viral etiologies of lower respiratory infections from children hospitalized in central Vietnam were detected by polymerase amplification assays. Total viral etiology was 46% and relative frequencies were 45% for influenza A virus, 42% for respiratory syncytial virus, 12% for adenoviruses, 8% for influenza B virus, and 5% both for parainfluenza type 1 and 3 virus. Influenza A (H1N1) 2009 virus was mainly responsible for infections in children from 3 months to 5 years of age. Detection of influenza A (H1N1) 2009 virus was performed both by isolation on MDCK cell culture and embryonated eggs and by amplification assays. In a group of 53 suspected patients A (H1N1) 2009 virus was detected in 32(60.4%) with a combination of both methods, and virus was isolated by cell culture in 24 patients. Characterization of HA and NA genes from representative isolates of influenza A (H1N1) 2009 virus was performed. Similarity of HA gene among Hue representative isolates are from 99.48% to 99.77% and similarity of NA sequences are from 99.57% to 99.86%. The sequences of HA and NA of Hue representative isolates were compared with 18 reference isolates from different countries showing similarity from 99.07% to 99.77% for HA and from 98.65% to 99.36% for NA sequences. Phylogenetic trees based on HA and NA sequences were constructed.

I documenti depositati in UnissResearch sono protetti dalle leggi che regolano il diritto d'autore