Abstract
BackgroundAvian influenza virus H9N2 is a panzootic pathogen that affects poultry causing mild to moderate respiratory distress but has been associated with high morbidity and considerable mortality. Interspecies transmission of H9N2 from avian species to mammalian hosts does occur. The virus possesses human virus-like receptor specificity and it can infect humans producing flu-like illness.MethodsRecently, mild influenza like symptoms were detected in H5N1 vaccinated flocks. Influenza A subtype H9N2 was isolated from the infected flock. The virus evolution was investigated by sequencing the viral genes to screen the possible virus recombination. The viral amino acid sequences from the isolated H9N2 strains were compared to other related sequences from the flu data base that were used to assess the robustness of the mutation trend. Changes in the species-associated amino acid residues or those that enabled virulence to mammals were allocated.ResultsPhylogenetic analyses of haemagglutinin and neuraminidase genes showed that the recently isolated Egyptian strain belonged to the H9N2 sub-lineage that prevails in Israel. The six internal segments of the isolated virus were found to be derived from the same sub-lineage with no new evidence of reassortment. The results demonstrated conserved genetic and biological constitution of H9N2 viruses in the Middle East. The recently isolated H9N2 virus from chicken in Egypt possessed amino acids that could enable the virus to replicate in mammals and caused severe disease in domestic chickens.ConclusionThe study highlights the importance of continuous monitoring of the mutations evolved in avian influenza viruses and its impact on virulence to avian species in addition to its importance in the emergence of new strains with the capacity to be a pandemic candidate.
Highlights
Avian influenza virus H9N2 is a panzootic pathogen that affects poultry causing mild to moderate respiratory distress but has been associated with high morbidity and considerable mortality
Direct human infections with avian H9N2 confirm that interspecies transmission of H9N2 from avian species to mammalian hosts occurs, and it is not uncommon [10]
We have found that the amino acid signatures in the A/chicken/Egypt/BSU-CU/2011 and H9N2 viruses circulated in the Middle East and most of the Egyptian H5N1 have possessed avian like amino acid signatures (Table 2)
Summary
Avian influenza virus H9N2 is a panzootic pathogen that affects poultry causing mild to moderate respiratory distress but has been associated with high morbidity and considerable mortality. Interspecies transmission of H9N2 from avian species to mammalian hosts does occur. After the transfer of the influenza viruses from the aquatic birds to a new avian or mammalian host, the viruses evolve rapidly and cause mild or occasionally severe respiratory disease [2]. H9N2 viruses are low pathogenic avian influenza (LPAI); they induce. Direct human infections with avian H9N2 confirm that interspecies transmission of H9N2 from avian species to mammalian hosts occurs, and it is not uncommon [10]. The disease in human is usually subclinical [11], and the virus has the opportunity to circulate and reassort with other influenza viruses
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