Pathological and Molecular Characterization of H5 Avian Influenza Virus in Poultry Flocks from Egypt over a Ten-Year Period (2009-2019)

Samah Mosad Mosad; Fatma A El-Gohary; Hanaa Said Ali; Hanem El-Sharkawy; Ehab Kotb Elmahallawy

doi:10.3390/ani10061010

Pathological and Molecular Characterization of H5 Avian Influenza Virus in Poultry Flocks from Egypt over a Ten-Year Period (2009-2019)

Animals (Basel). 2020 Jun 9;10(6):1010. doi: 10.3390/ani10061010.

Authors

Samah Mosad Mosad¹, Fatma A El-Gohary², Hanaa Said Ali³, Hanem El-Sharkawy⁴, Ehab Kotb Elmahallawy^{5

6}

Affiliations

¹ Department of Virology, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt.
² Department of Hygiene and Zoonoses, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt.
³ Department of Pathology, Animal Health Research Institute, Mansoura Branch, Mansoura 35516, Egypt.
⁴ Department of Poultry and Rabbit Diseases, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh 33511, Egypt.
⁵ Department of Biomedical Sciences, University of León, 24071 León, Spain.
⁶ Department of Zoonotic diseases, Faculty of Veterinary Medicine, Sohag University, Sohag 82524, Egypt.

Abstract

Avian influenza virus (AIV) remains one of the enzootic zoonotic diseases that challenges the poultry industry in Egypt. In the present study, a total of 500 tissue samples were collected from 100 chicken farms (broilers and layers) suspected to be infected with AIV through the period from 2009 to 2019 from Dakahlia governorate, Egypt. These samples were pooled in 100 working samples and screened for AIV then the positive samples were subjected to histopathological examination combined with real time-polymerase chain reaction (RRT-PCR). RRT-PCR positive samples were also subjected to conventional reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of H5 AIV and some of these resulting positive samples were sequenced for detection of the molecular nature of the studied virus. Interestingly, the histopathological examination revealed necrotic liver with leukocytic infiltration with degenerative changes with necrotic pancreatitis, edema, and intense lymphoid depletion of splenic tissue and hyperplastic tracheal epithelium. Likewise, edema and congested sub mucosal blood vessels and intense bronchial necrosis with hyalinized wall vascular wall and heterophils infiltration were reported. Pneumonic areas with intense leukocytic aggregation mainly and vasculitis of the pulmonary blood vessels were also detected in lung. Collectively, these significant pathological changes in examined tissues cohered with AIV infection. Regarding the molecular characterization, 66 samples were positive for AIV by RRT-PCR and 52 of them were positive for H5 AIV by RT-PCR. The phylogenetic analysis revealed that the H5 viruses identified in this study were aligned with other Egyptian H5N1 AIVs in the Egyptian sub clade 2.2.1, while some of the identified strains were aligned with other Egyptian H5N8 strains in the new Egyptian sub clade 2.3.4.4. Taken together, our present findings emphasize the wide spread of AIV in Egypt and the importance of developing an efficient surveillance and periodical screening program for controlling such disease of public health concern.

Keywords: Egypt; H5; avian influenza; characterization; molecular; pathological.