Characterization of Highly Pathogenic Avian Influenza H5N8 Virus from Egyptian Domestic Waterfowl in 2017

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Avian Pathol. 2018 Apr 27:1-35. doi: 10.1080/03079457.2018.1470606. [Epub ahead of print]
Characterization of Highly Pathogenic Avian Influenza H5N8 Virus from Egyptian Domestic Waterfowl in 2017.

Anis A¹, AboElkhair M², Ibrahim M³.
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Abstract

In 2016, the highly pathogenic avian influenza (HPAI) H5N8 virus was detected in wild birds for the first time in Egypt. In the present study, we identified the HPAI virus H5N8 of clade 2.3.4.4 from domestic waterfowl in Egypt, suggesting its transmission to the domestic poultry from the migratory birds. Based on partial hemagglutinin (HA) gene sequence, this virus has a close genetic relationship with subtype H5N8 viruses circulating in Asia and Europe. Pathologically, H5N8 virus in hybrid duck induced nervous signs accompanied by encephalomalacia, hemorrhages, nonsuppurative encephalitis and nonsuppurative vasculitis. The granular layer of cerebellum showed multifocal areas of hydropic degeneration and the Purkinje cell neurons were necrotized or lost. Additionally, the lung, kidney and spleen were congested, and necrotizing pancreatitis was also observed. The co-circulation of both HPAI H5N1 and H5N8 subtypes with the low pathogenic avian influenza H9N2 subtype complicate the control of AI in Egypt with the possibility of emergence of new reassortant viruses. Therefore, continuous monitoring with implementation of strict control measures is required.


KEYWORDS:

Egypt; H5N8; HA gene; HPAI; RT-PCR; histopathology; waterfowl

PMID: 29701481 DOI: 10.1080/03079457.2018.1470606