Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral passaging in broilers and its relatedness to pathogenicity and amino acid (a.a) sequences of the hemagglutinin (HA) cleavage site and neuraminidase (NA) stalk. The original H9N2 AI vir...

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...

In 2009, a novel H1N1 influenza (pH1N1) virus caused the first influenza pandemic in 40 y. The virus was identified as a triple reassortant between avian, swine, and human influenza viruses, highlighting the importance of reassortment in the generation of viruses with pandemic potential. Previously, we showed that a reassortant virus composed of wild-type avian H9N2 surface genes in a seasonal ...

To prevent H9N2 avian influenza virus infection in chickens, a long-term vaccination program using inactivated vaccines has been implemented in China. However, the protective efficacy of inactivated vaccines against antigenic drift variants is limited, and H9N2 influenza virus continues to circulate in vaccinated chicken flocks in China. Therefore, developing a cross-reactive vaccine to control...

Avian influenza (AI) is an acute infectious disease with worldwide significance causing extensive economic losses in the poultry industry. Avian influenza viruses (AIVs) belong to the family Orthomyxoviridae and categorized in the genus influenza virus A. These viruses have been isolated from more than 100 species of free-living birds. Migratory birds are considered as reservoirs for AIVs and a...

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...

Bacterial co-infections can probably influence the pathogenicity of H9N2 low pathogenic avian influenza virus (AIV). This study aimed to evaluate the effect of exposure time to Escherichia coli (O:2) on the pathogenicity of H9N2 AIV in broiler chickens. Three hundred and sixty broiler chickens were randomly allocated to six equal groups. At the age of 26 days, all chicks except groups 5 and 6 w...

an experimental inactivated oil-emulsion h9n2 avian influenza vaccine was formulated with 3 parts ofinactivated avian influenza antigen a/chicken/iran/101/1998(h9n2) emulsified in 7 parts of oil adjuvant.twelve week-old specific pathogen-free (spf) chickens were divided into seven groups of 10 birds. sixgroups were vaccinated with 1, 1/10th, 1/50th, 1/100th, 1/200th and 1/400th field dose of th...

Low Pathogenicity Avian Influenza virus subtype H9N2 causes decreased egg production and two of the four defined poultry lineages (G1 Y280) have been associated with human infections. The high positive test results for in LBMs Greater Jakarta area 2021 can be a source transmission surrounding area. This study aims to determine prevalence risk factors that play role contamination obtain multivar...

Most low-pathogenicity avian influenza (LPAI) viruses cause no or mild disease in avian species. Little is known about the mechanisms of host defence and the immune responses of avian influenza-infected birds. This study showed that chicken macrophages are susceptible to infection with LPAI H9N2 and H6N2 viruses and that infection led to apoptosis. In H9N2 virus-infected chicken macrophages, To...