A current view of the emergence of pandemic influenza viruses envisages a gene flow from the aquatic avian reservoir to humans via reassortment in pigs, the hypothetical "mixing vessel." Understanding arising from recent H5N1 influenza outbreaks in Hong Kong since 1997 and the isolation of avian H9N2 virus from humans raises alternative options for the emergence of a new pandemic virus. Here we...

The origin of the H5N1 influenza viruses that killed six of eighteen infected humans in 1997 and were highly pathogenic in chickens has not been resolved. These H5N1 viruses transmitted directly to humans from infected poultry. In the poultry markets in Hong Kong, both H5N1 and H9N2 influenza viruses were cocirculating, raising the possibility of genetic reassortment. Here we analyze the antige...

H5N1 and H9N2 avian influenza virus subtypes top the World Health Organization's list for the greatest pandemic potential. Inactivated H5N1 vaccines induce limited immune responses and, in the case of live-attenuated influenza virus vaccines (LAIV), there are safety concerns regarding the possibility of reassortment between the H5 gene segment and circulating influenza viruses. In order to over...

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, S...

influenza Avirus subtype H7N1 antigen to find out its relatedness by means of the HI assay. The H7 antigen reacted with WHO reference antibodies to high titers (HI titer, 320), indicating antigenic similarity with influenza A(H7N9) isolated from China. This revealed the appropriateness of using the H7 virus antigen in the study. All serum samples from the high-risk group and the general populat...

background and aims: avian influenza (ai) h9n2 subtype was first reported to infect turkeys in the united states in 1966 and has been panzootic in eurasia. in iran, the h9n2 virus was first isolated from broiler chickens in 1998 in ghazvin province and it is the most prevalent subtype of influenza virus in poultry industry in iran at the present time. materials and methods: in this study, we se...

H9N2 influenza A viruses have become established worldwide in terrestrial poultry and wild birds, and are occasionally transmitted to mammals including humans and pigs. To comprehensively elucidate the genetic and evolutionary characteristics of H9N2 influenza viruses, we performed a large-scale sequence analysis of 571 viral genomes from the NCBI Influenza Virus Resource Database, representing...

Background and Aims: Avian Influenza (AI) H9N2 subtype was first reported to infect turkeys in the United States in 1966 and has been panzootic in Europe and Asia. The impact of avian influenza caused by H9N2 viruses in Iran is now significantly more severe than in previous years. Methods: Sequence analysis and phylogenetic study of the complete coding region Polymerase A (PA) gene of H9N2 subt...

In 1997, an avian H5N1 influenza virus, A/Hong Kong/156/97 (A/HK/156/97), caused six deaths in Hong Kong, and in 1999, an avian H9N2 influenza virus infected two children in Hong Kong. These viruses and a third avian virus [A/Teal/HK/W312/97 (H6N1)] have six highly related genes encoding internal proteins. Additionally, A/Chicken/HK/G9/97 (H9N2) virus has PB1 and PB2 genes that are highly relat...

avian influenza is one of the most important diseases in avian industry, which also threats human population. thus, vaccination is necessary for controlling this viral disease. in this study, killed vaccine of avian influenza subtype h9n2 and formalin solution (for virus inactivation) were used. it is necessary to study the effect of different factors such as formalin concentration, as well as ...