Ameliorative Effect of Azolla Pinnata Ethanolic Extract on Ranitidine-Induced Hepatotoxicity in Rats

Abstract

in the present study, samples were collected from wild and domestic waterfowls to detect currently circulating HPAI H5Nx viruses. All H5Nx detected in migratory ducks were characterized as HPAIV H5N8, clade 2.3.4.4b, while domestic waterfowls viruses belonged to HPAIV H5N1, clade 2.2.1.2. Partial HA gene sequencing followed by phylogenetic analysis of the obtained sequences of five selected isolates was performed. Phylogenetic analysis revealed clustering of the three H5N8 isolates in clade 2.3.4.4b, with other Egyptian H5N8 isolates with amino acid identity percent with each other ranging from (96.9% - 99.3%). The two H5N1 isolates clustered in clade 2.2.1.2 with other current Egyptian isolates. The amino acid identity percent between vaccinal strains and H5N8 field isolates rangef from (88.2% - 89.6%) wwhile identitiy with H5N1 field isolates was (96.5% - 99%). The amino acid identity percent between H5N8 and H5N1 field isolates was (86.3% - 87.8%). Antigenic analysis of currently circulating HPAI H5Nx of different clades were conducted using cross HI test using hyperimmune sera raised against (A/Teal/Egypt/Damietta-1/2016/H5N8 and A/Geese/Egypt/ Men-21/2016/H5N1) and three commonly used commercial vaccinal strains. The antigenic relatedness between the two HPAI local isolates (H5N1 and H5N8) was low (R value 24.8%) indicating major antigenic difference between the two subtypes. Also, a major subtype difference in antigenicity (R value 20.7-31.0%) was also detected between the local HPAI H5N8 isolate and the three vaccinal strains. While, a minor subtype difference (R value 38.7-68.7%) was detected among the examined H5N1 local isolate and the three vaccinal strains. Our results support that, HPAI H5N8 virus is genetically and antigenically distinct from HPAI H5N1 virus. Also, some commercial vaccines which are used to control avian influenza in Egypt are genetically and antigenically distinct from HPAI H5N8 virus currently circulating in Egypt. These findings necessitates updating the HA of H5 Vaccine to be genetically and antigenically closer to the field viruses together with, regular monitoring of wild birds to predict and prevent possible AIV outbreaks.