First detection of avian influenza subtype H4N6 in Israel in a wild mallard (Anas platyrhynchos).

Avian influenza viruses (AIV) are a worldwide threat to animal and human health. As wild waterfowl circulate and spread these viruses around the world, investigations of AIV prevalence in wild populations are critical for understanding pathogen transmission, as well as predicting disease outbreaks in domestic animals and humans. Surveillance efforts in this study have isolated H4N6 for the first time in Israel from a faecal sample of a wild mallard (Anas platyrhynchos). Phylogenetic analyses of the HA and NA genes revealed that this strain is closely related to isolates from Europe and Asia. This Eurasian origin, together with Israel serving as an important migratory bottleneck of the mid Palearctic-African flyway, suggests a potential introduction of this strain by migratory birds. Additional phylogenetic analysis of the isolate's internal genes (PB1, PB2, PA, NP, M and NS) revealed high levels of phylogenetic relatedness with other AIV subtypes, indicating previous reassortment events. High reassortment rates are characteristic for H4N6 viruses, which, together with this subtype's ability to infect pigs and adaptability to the human receptor binding domain, raises the concern that it would potentially become zoonotic in the future. These results emphasize the importance of continuous AIV monitoring in migratory birds.

Genetic characterization of HA gene of low pathogenic H9N2 influenza viruses isolated in Israel during 2006-2012 periods.

H9N2 influenza viruses are isolated in Israel since 2000 and became endemic. From November 2006 to the beginning of 2012, many H9N2 viruses were identified, all belonged to the Asian G1-like lineage represented by A/qu/Hong Kong/G1/97 (H9N2). In the present study, 66 isolates were selected for their hemagglutinin gene characterization. Most H9N2 isolates were distributed between two main groups, identified as the 4th and 5th introductions. The 5th introduction, was represented by a compact cluster containing viruses isolated in 2011-2012; the 4th introduction was subdivided into two subgroups, A and B, each containing at least two clusters, which can be identified as A-1, A-2, B-1, and B2, respectively. Genetic analysis of the deduced HA proteins of viruses, belonging to the 4th and 5th introductions, revealed amino acid variations in 79 out of 542 positions. All isolates had typical low pathogenicity motifs at the hemagglutinin (HA) cleavage site. Most viruses had leucine at position 216 in a receptor binding pocket that enables the virus to bind successfully with the cellular receptors intrinsic to mammals, including humans. It was shown that the differences between the HA proteins of viruses used for vaccine production and local field isolates increased in parallel with the duration and intensity of vaccine use, illustrating the genetic diversity of the H9N2 viruses in Israel.

Isolation and identification of highly pathogenic avian influenza virus subtype H5N1 from emus from the Ein Gedi oasis by the Dead Sea.

An avian influenza virus (AIV), A/Emu/Israel/552/2010/(H5N1), was isolated from a dead emu that was found in the Ein Gedi oasis near the Dead Sea. The virus molecular characterization was performed by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time RT-PCR using AIV subtype-specific primers. The virus was of high pathogenicity, according to its intravenous pathogenicity index of 2.85 and the nucleotide sequencing at the cleavage site of the hemagglutinin gene, GERRRKKR, which is typical for highly pathogenic chicken influenza A viruses.