Characterization and Phylogenetic Analysis of the Hemagglutinin Gene in H9 Influenza Viruses from Chickens in Morocco from 2017 to 2019

Abstract

Since the early 2000s, the avian influenza virus (AIV) subtype H9N2 has been widely circulating in North African countries, including Libya, Tunisia, and Egypt. For unknown reasons, H9N2 was not detected in Moroccan farms until the end of 2016, and at present, it is endemic in poultry. This study was carried out to evaluate the evolution of H9 AIVs in Morocco from 2017 to 2019. In this study, 16 H9 viruses collected from 2017 to 2019 in Morocco were isolated and sequenced. The genomic signatures and protein sequences of these isolates were analyzed. Moroccan H9 viruses were closely related to viruses isolated from African and Middle Eastern countries, and the hemagglutinin gene resembled those of viruses of G1-like lineage, and multiple mammalian host-associated mutations were detected that favor transmission from avian to mammalian hosts. Other mutations related to virulence were also identified. Our findings suggest that attention be given to the control of H9N2 influenza viruses in chickens and continuous monitoring of the prevalence and pathogenic potential of AIV H9N2 in the poultry population in Morocco.

Keywords: H9; Morocco; influenza virus; phylogenetic analyses.