Comparison of in vitro antiviral activity of tea polyphenols against influenza A and B viruses and structure-activity relationship analysis.

Influenza poses a particular risk of severe outcomes in the elderly, the very young and those with underlying diseases. Tea polyphenols are the natural phenolic compounds in teas, and principally consist of catechins, proanthocyanidins, flavonols, and theaflavins, which antiviral activities have been reported recently. This study is to gain a further insight into potential of various tea polyphenols for inhibiting influenza virus infection.

The tree shrew provides a useful alternative model for the study of influenza H1N1 virus.

Background: The influenza pandemics have resulted in significant morbidity and mortality worldwide. Animal models are useful in the study of influenza virus pathogenesis. Because of various limitations in current laboratory animal models, it is essential to develop new alternative animal models for influenza virus research aimed at understanding the viral and host factors that contribute to virus infection in human.

[The effects of a hot water soluble extract (S-03) isolated from Isatis indigotica root on influenza A and B viruses in vitro].

This study was to investigate the antiviral effects of a hot water soluble extract S-03 isolated from Isatis indigotica root on different subtypes of influenza A and B viruses in MDCK cell cultures, using plaque reduction, immunofluorescence and hemo-agglutination inhibition (HAD) assays. Chemical analysis of the extract S-03 showed that it contained high proportion of polysaccharides. The antiviral effects in vitro showed that the S-03 had no effect on different influenza viruses if the drug was used before virus adsorption, but S-03 showed obvious activities against influenza viruses if treatment after virus adsorption or direct reaction of drug and virus before virus adsorption.

[A pathogenic and clinical study of 882 cases of adult influenza-like illness in Guangzhou].

Objective: This study was undertaken to describe the viral etiology and clinical features in patients with influenza-like illness (ILI) in Guangzhou.

Methods: The nasopharyngeal and throat swabs were collected from 882 patients presenting with ILI between January and September, 2009. Viral pathogens were cultured and identified by immunofluorescence technique using the Shell-Vial method.