Abstract
Low pathogenic H9N2 avian influenza (LPAI H9N2) is considered one of the most important diseases found in poultry (broiler, laying hens, breeding chickens, and turkeys). This infection causes considerable economic losses. The objective of this work was to monitor and assess the presence of avian influenza virus (AIV) H9N2 in eight different regions of Morocco using real-time RT-PCR, and to assess the phylogenetic and molecular evolution of the H9N2 viruses between 2016 and 2019. Field samples were collected from 108 farms suspected of being infected with LPAI H9N2 virus. Samples were analyzed using H9N2-specific real-time RT-PCR. Highly positive samples were subjected to virus isolation and seven isolates were fully sequenced. Low pathogenic H9N2 avian influenza virus was introduced in Morocco in 2016. We show that in 2018–2019, the virus was still present irrespective of vaccination status. Phylogenetic and molecular analyses showed mutations related to virulence, although our viruses were related to 2016 Moroccan viruses and grouped in the G1 lineage. Specific amino acid substitutions were identified in Moroccan H9N2 viruses that are believed to lead to increased resistance to antiviral drugs.
Highlights
Our sampling was based on chickens suspected of being infected with low pathogenic virus (LPAI) H9N2 virus, and presenting respiratory signs, associated with a decrease in food consumption and a drop in production
One hundred and fifty-one samples from respiratory tissues and tracheal swabs were collected between June 2018 and May 2019 from different areas of Morocco: Fes-Meknes, Rabat-Sale-Kenitra, Casablanca-Settat, Draa-Tafilalet, Benimellal-Khenifra, Souss-Massa, Marrakech-Safi, and the eastern region
Our analysis included 151 field samples from 108 poultry farms suspected of being infected by the LPAI H9N2 virus and presenting mainly respiratory signs as well as poor zootechnical performances, as reported previously [39]
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Low pathogenic H9N2 avian influenza is an emerging disease that causes important economic losses in the poultry sector and is considered a threat to both poultry farms and public health. Being a member of the genus Alphainfluenzavirus, and of the family Orthomyxoviridae, avian influenza viruses are enveloped RNA virus, with a genome composed of eight negative-sense RNA segments [1]. They are classified as low or highly pathogenic, on the basis of their virulence and hemagglutinin (HA) and neuraminidase (NA) sequences [2]
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