Genetic characterization of H5N1 influenza virus that caused new outbreak in Israel at the beginning of 2008.

Our aim was to characterize the A/ck/Israeli/1055/2008 (H5N1) avian influenza virus that was isolated at the beginning of 2008, and to establish the phylogenetic relationship of this isolate to other H5N1 viruses that were recently isolated in adjacent countries. In light of a study of complete nucleotide sequences of all the genes we found that the isolate (year 2008) was closely related to the H5N1 viruses isolated in Egypt, Israel and Gaza in 2006. The Israeli isolate had the hemagglutinin-connecting peptide with a polybasic amino acid insertion. The most host-restriction sites of the 2008 isolate were typical of avian hosts, with one exception: K627 at the PB2 protein. As compared with previous local H5N1 isolates, a high mutation rate was found at the HA gene, which antigenic sites were under positive selection pressure.

Genetic characterization of avian influenza viruses isolated in Israel during 2000-2006.

Our aim was to establish the phylogenetic and genetic relationships among avian influenza viruses (AIV) recently isolated from poultry in Israel. During this study we analyzed complete nucleotide sequences of two envelope (hemagglutinin and neuraminidase) and six internal genes (polymerase B1, polymerase B2, polymerase A, nucleoprotein, nonstructural, and matrix) of 29 selected H9N2 and six internal genes of five H5N1 viruses isolated in Israel during 2000-2006. Comparative genetic and phylogenetic analyses of these sequences revealed that the local H5N1 viruses are closely related to H5N1 viruses isolated in European, Asian, and Middle Eastern countries in 2005-2006. The H9N2 Israeli isolates, together with viruses isolated in Jordan and Saudi Arabia formed a single group. Our data support the claim that during recent years a new endemic focus of H9N2 has been formed in the Middle East. The introduction of H5N1 and co-circulation of these two subtypes of AIV in this region may augment the risk of potentially pandemic strains emergence.

Molecular characterization of the glycoprotein genes of H5N1 influenza A viruses isolated in Israel and the Gaza Strip during 2006 outbreaks.

Highly pathogenic H5N1 avian influenza A viruses (AIV) have caused outbreaks among domestic poultry and wild aquatic birds in many Asian, European, and African countries since 1997. In March 2006 an avian H5N1 influenza A virus was isolated from poultry in Israel. In the present study we molecularly characterized the hemagglutinin (HA) and neuraminidase (NA) genes of eleven H5N1 viruses isolated from domestic poultry in Israel and Gaza in March-April 2006. Phylogenetic analysis of the HA and NA genes showed that the Israeli and Gazian viruses were closely related to viruses isolated in Egypt in 2006.

Genetic analysis of nonstructural genes (NS1 and NS2) of H9N2 and H5N1 viruses recently isolated in Israel.

The avian influenza virus subtype H9N2 affects wild birds, domestic poultry, swine, and humans; it has circulated amongst domestic poultry in Israel during the last 6 years. The H5N1 virus was recorded in Israel for the first time in March 2006. Nonstructural (NS) genes and NS proteins are important in the life cycle of the avian influenza viruses. In the present study, NS genes of 21 examples of H9N2 and of two examples of H5N1 avian influenza viruses, isolated in Israel during 2000-2006, were completely sequenced and phylogenetically analyzed. All the H9N2 isolates fell into a single group that, in turn, was subdivided into three subgroups in accordance with the time of isolation; their NS1 and NS2 proteins possessed 230 and 121 amino acids, respectively. The NS1 protein of the H5N1 isolates had five amino acid deletions, which was typical of highly pathogenic H5N1 viruses isolated in various countries during 2005-2006. Comparative analysis showed that the NS proteins of the H9N2 Israeli isolates contained few amino acid sequences associated with high pathogenicity or human host specificity.

Multifocal avian influenza (H5N1) outbreak.

During March 2006, an outbreak of highly pathogenic avian influenza (H5N1) occurred in multiple poultry farms in Israel. The epidemiologic investigation and review of outbreak mitigation efforts uncovered gaps in planning for and containing the outbreak, thus affording valuable lessons applicable to other countries in similar settings.

Genetic characterization of the H9N2 influenza viruses circulated in the poultry population in Israel.

The partial nucleotide sequences of the hemagglutinin (HA) genes of 72 H9N2 influenza viruses isolated from chickens and turkeys in Israel during the period 2000-2005 were genetically analyzed. The isolates possessed the three types of amino acid motif -R-S-S-R/G-L-, -R-S-N-R/G-L-, and -R-S-K-R/G-L- at the cleavage site of HA. Phylogenetic analyses showed that all Israeli isolates belonged to the same group which further divided into three closely related sub-groups. The HA genes of these isolates were related to the HA gene of A/chicken/Germany/R45/98 isolated from chicken in Germany in 1998.

Phylogenetic relationships of West Nile viruses isolated from birds and horses in Israel from 1997 to 2001.

In November 1997, an outbreak of a neuroparalytic disease caused by West Nile (WN) virus was diagnosed in young goose flocks. Domestic geese were similarly affected in the late summer and fall of 1998, 1999, 2000 and 2001. WN viruses were also isolated from migratory and wild birds and horses in 1998-2001. A 1278 bp sequence of the envelope gene of 24 Israeli WN virus isolates was compared with those of seven isolates from Africa, Europe and New York. As a result, the Israeli isolates could then be grouped into two clusters. The 15 avian and three equine from 1997-2001 in the first cluster of viruses were shown to be identical to WN-NY99, while the second cluster comprised one goose isolate from 1998 and two goose and two pigeon isolates from 2000. These closely resembled the most recent Old World isolates, and indicate that at least two WN genotypes were co-circulating in the region during this time.

Introduction of West Nile virus in the Middle East by migrating white storks.

West Nile virus (WNV) was isolated in a flock of 1,200 migrating white storks that landed in Eilat, a town in southern Israel, on August 26, 1998. Strong, hot westerly winds had forced the storks to fly under considerable physical stress before reaching the agricultural land surrounding the town. Most of the flock were fledglings, <1 year old, which had hatched in Europe. Thirteen dead or dying storks were collected 2 days after arrival and submitted to the laboratory for examination. Four WNV isolates were obtained from their brains. Out of 11 storks tested six days after arrival, three had WNV-neutralizing antibodies. Comparative analysis of full-length genomic sequences of a stork isolate and a 1999 flamingo isolate from the USA showed 28 nucleotide (nt) (0.25%) and 10 amino acid (0.3%) changes. Sequence analysis of the envelope gene of the stork isolate showed almost complete identity with isolates from Israeli domestic geese in 1998 and 1999 and from a nonmigrating, white-eyed gull in 1999. Since these storks were migrating southwards for the first time and had not flown over Israel, we assume that they had become infected with WNV at some point along their route of migration in Europe.