background and aims: hemagglutinin (ha) protein of avian influenza (ai) plays an essential role in the virus pathogenicity. ai h9n2 subtype causes significant economic loss in broiler and layer in poultry farms in iran. ai viruses have a great involvement in evolutionary changes at nucleotide and amino acid levels and vaccines could induce faster rates of such changes. up-dated understanding of...

background : avian influenza virus (aiv) infection is a major cause of bird and human morbidity and mortality. we aimed to evaluate a specific and sensitive multiplex rt-pcr that can simultaneously detect influenza type a viruses and differenti­ate the two most important subtypes of avian influenza viruses h7 and h9 subtypes. methods : a multiplex reverse transcriptase-polymerase chain reaction...

influenza a viruses possesses two virion surface glycoproteins including haemagglutinin (ha) and neuraminidase (na). the na plays an important role in viral replication and promotes virus release from infected cells and facilitates virus spread throughout the body. to find out any genomic changes that might be occurred on na gene of avian influenza circulating viruses, we have genetically analy...

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 ...

influenza is a contagious viral disease that is seen in avian, human and other mammals, so its control is important. vaccination against influenza virus subtype h9n2 is one of the ways in controlling program, for this reason several vaccines has been produced. recently, application of inactivated oil-emulsion vaccines in poultry for controlling low pathogenic avian influenza is increasing. at p...

Most highly pathogenic avian influenza viruses (AIV) emerge after field passage of non-pathogenic AIVs in birds. The outbreak of low-pathogenic H7N1 avian influenza virus in Italy during 1999-2000 followed by outbreak of highly pathogenic H7N1 avian influenza virus is one example in this regard. This experiment has been designed to investigate the effect of pre-infection of birds with LPAI on s...

Avian influenza is an important disease of poultry with the potential to cause major epidemics resulting in significant economic losses. The presence of avian influenza viruses (AIV) in chickens in Iran has not been previously reported. An avian influenza outbreak in broiler, layer and breeder farms occurred during a very hot summer in July 1998. Three AIV isolates designated as 101, 102 and 10...

Avian influenza viruses (AIV) affect a wide range of birds and mammals, cause severe economic damage to the poultry industry, and pose a serious threat to humans. Highly pathogenic avian influenza viruses (HPAI) H5N1 were first identified in Southeast Asia in 1996 and spread to four continents over the following years. The viruses have caused high mortality in chickens and various bird species ...

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...

although migratory waterfowl is well known to be a major reservoir for avian influenza virus (aiv), there are only few recently published reports about the seroprevalence of aiv in this group of birds. to investigate the aiv antibody status in migratory waterfowl of iran, we collected 217 serum samples from 25 different species of waterfowl during 2003 and 2004. these serum samples were tested ...