The effect of the extracts of Echinacea purpurea and Sambucus nigra (black elderberry) on virus shedding in H9N2 avian influenza infected chickens

Summary Previous studies have shown antiviral effect of Echinacea and elderberry preparations against human influenza viruses in vitro. To investigate the in vivo antiviral effect of these herbs on avian H9N2 influenza virus, amantadine and two standardized commercial extracts of Echinacea purpurea (EF) and Sambucus nigra (SAM) were used in broiler chickens infected with H9N2 strain of the virus. EF, SAM and amantadine were added to drinking water of chickens in different groups for 7 days starting 8 h after intranasal inoculation of the challenged virus and in prophylaxis group of EF for 10 days starting 5 days before the challenge time. During post infection (PI) days, titer of the virus in tracheal mucosa and faeces were quantified using quantitative real-time PCR. The untreated challenged group showed the highest faecal and tracheal titer of the virus on day 3 PI. The virus was not detected in negative control group during the course of the experiment. Prophylaxis administration of EF considerably reduced the faecal titer of the virus in all days PI. Although overall titer of the virus in the tracheal samples was low, treatment with amantadine and SAM apparently reduced quantity of tracheal positive samples in comparison to untreated and EF-treated groups. This study indicates that using Echinacea and elderberry extracts in chicken can reduce H9N2 virus shedding from trachea and faeces