Molecular pathogenic and host range determinants of reassortant Egyptian low pathogenic avian influenza H9N2 viruses from backyard chicken

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Int J Vet Sci Med. 2019 Jul 11;7(1):10-19. doi: 10.1080/23144599.2019.1637046. eCollection 2019. Molecular pathogenic and host range determinants of reassortant Egyptian low pathogenic avian influenza H9N2 viruses from backyard chicken.

Samir A¹, Adel A¹, Arafa A¹, Sultan H², Hussein Ahmed HA³.
Author information

1 Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Giza, Egypt. 2 Avian and Rabbit Diseases Dept., Faculty of Veterinary Medicine, University of Sadat, City Sadat, Minoufiya, Egypt. 3 Virology Dept., Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.

Abstract

Since the introduction of H9N2 low pathogenic avian influenza virus in Egypt, it became an endemic disease causing considerable economic losses in different poultry sectors especially in the presence of other secondary bacterial and viral infections. The H9N2 viruses in Egypt are in continuous evolution that needs deep analysis for their evolution pattern based on the genetic constitutions of the pathogenic determinant genes (HA, PB2, PB1, PA, and NS). In this work, samples were collected from the backyard chickens from 3 Egyptian governorates. Five selected viruses were sequenced and analyzed for the hemagglutinin gene which showed genetic relatedness to the Asian G1 lineage group B, similar to the circulating H9N2 viruses in Egypt since 2013. The sequence for PB2, PB1, PA, HA and NS genes of the selected five viruses indicate a natural re-assortment event with recent Eurasian subtypes and similar to Egyptian H9N2 virus isolated from pigeon in Egypt during 2014. The Egyptian viruses of our study possess amino acids signatures including S42, V127, L550, L672 and V504 in the internal genes NS1, PA, and PB2, of respectively of an impact on virus transmission and replication. This work indicates that the H9N2 is in continuous evolution with alarming to the reassortment occurrence.
? 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.


KEYWORDS:

Hemagglutinin; LPAI H9N2; NS; PA; PB1; PB2

PMID: 31620483 PMCID: PMC6776986 DOI: 10.1080/23144599.2019.1637046