Phylogenetic analysis of hemagglutinin, neuraminidase, and nucleoprotein genes of H9N2 avian influenza viruses isolated in Israel during the 2000-2005 epizootic.

The first two isolates of H9N2 influenza virus in Israel were collected from turkey and chicken hosts in May 2000. The actual epizootic of the H9N2 virus started in December 2001, after a 1.5-year period of silence, and still continues.

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.

Ecology and molecular epidemiology of H9N2 avian influenza viruses isolated in Israel during 2000-2004 epizootic.

The first two isolates of H9N2 influenza virus were picked up from turkey and chicken hosts in May 2000, but the actual epizootic of the low pathogenicity avian influenza (LPAI) H9N2 virus started in December 2001, following a 1.5-year period of silence, during which the H10N7 and H6N3 influenza viruses were isolated sporadically. The outbreak of the H9N2 influenza began in northern Israel, from where the epizootic spread all over the country.

Nucleotide sequence of the matrix protein gene of avian paramyxovirus, serotype 3b: evidence on another member of the suggested new genus of the subfamily Paramyxovirinae.

The complete nucleotide sequence of the gene encoding the matrix protein (M) of the avian paramyxovirus, serotype 3b (APMV-3b), has been determined by means of the direct sequencing of viral RNA using reverse transcriptase reaction. The adjacent portions of the neighboring phosphoprotein (P) and fusion (F) protein genes were also sequenced that permitted to determine the consensus sequence of the viral genome, the poly(A) tract, downstream and upstream non-coding portions of the P and F genes, respectively, as well as the corresponding intergenic regions. The gene is 1478 nucleotides long with a protein-coding sequence of 1194 nucleotides.

Antigenic heterogeneity amongst the field isolates of Newcastle Disease Virus (NDV) in relation to the vaccine strain. Part II: studies on viruses isolated from domestic birds in Israel.

Forty three Newcastle disease virus (NDV) strains isolated before and during 1997 in Israel from domestic birds were studied by means of the three panels of monoclonal antibodies prepared against all the viral envelope proteins in order to reveal the possible antigenic differences between them and the VH strain used in Israel for poultry vaccination. Three isolates were found to have significant antigenic differences in the hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins as compared to the vaccine strain. As to the matrix protein, almost all the viruses isolated during the year 1997 were found to have considerable differences from the vaccine strain in two of four antigenic sites.

Antigenic heterogeneity among the field isolates of Newcastle disease virus (NDV) in relation to the vaccine strain: 1. Studies on viruses isolated from wild birds in Israel.

In order to reveal the viruses strongly differing from the VH NDV strain used in Israel for poultry vaccination, 54 NDV strains isolated during the last 15 years in Israel from feral birds were studied by means of the panels of 39 monoclonal antibodies. Six isolates were found to have considerable antigenic differences in envelope proteins as compared to the vaccine strain. In four cases, the differences were related mostly to the hemagglutinin-neuraminidase glycoprotein, in one case to the fusion glycoprotein, and in one case to the matrix protein.

The comparative antigenic characterization of Newcastle disease virus strains isolated in Kenya and Kazakhstan.

Twenty six Newcastle disease viruses--12 reference strains and 14 strains isolated in Kenya and Kazakhstan--were characterized by means of a large panel of 38 monoclonal antibodies (MAB) directed against all the three envelope proteins: matrix, hemagglutinin-neuraminidase and fusion. The essential distinctions were revealed between the viruses isolated in Kenya and Kazakhstan while the differences amongst the viruses belonging to the same local group were much smaller. The heterogeneity amongst the viruses isolated in Kenya was more expressed as compared to the Kazakhstanian strains.

Antigenic characterization of the nucleocapsid protein of Newcastle disease virus by means of a new panel of monoclonal antibodies.

Nine monoclonal antibodies (MAB) against nucleocapsid protein (NP) of Newcastle disease virus (NDV) have been prepared and characterized. All the MABs were classified into three groups by means of the competitive binding assay. At least three antigenic sites were delineated on the NP.

Comparative characteristics of the Israeli Newcastle disease virus field strains by means of a wide panel of monoclonal antibodies against hemagglutinin-neuraminidase glycoprotein.

Fourteen mouse monoclonal antibodies (MAB) were tested for their ability to react with 15 reference and 52 local Newcastle disease virus (NDV) strains isolated in Israel during the last decade from feral birds. All the field isolates had no antigenic difference when examined by classic serological tests. However, MAB-mediated analysis revealed wide antigenic heterogeneity amongst the studied viruses.

Isolation of avian serotype 3 paramyxoviruses from imported caged birds in Israel.

Ten avian serotype 3 paramyxoviruses were isolated for the first time in Israel from passerine and psittacine imported caged birds. The birds were submitted for investigation of an illness characterized by nonspecific signs of weakness, anorexia, vomiting, and sneezing. In addition, only the parakeets developed specific neurologic signs.

Avian paramyxoviruses serotype 3 isolated from captive birds in Israel: clinical signs, pathology, and antigenic characterization.

Thirteen HA agents were isolated in Israel from captive flamingoes (Phoenicopterus ruber), Egyptian geese (Alopochen aegyptiacus) belonging to order Anseriformes, and ibis (Guara rubra) belonging to order Ciconiiformes. The isolation was done from postmortem materials in three cases of severe respiratory disease with high mortality. The isolates were examined serologically and identified as belonging to the serotype 3 of avian paramyxoviruses (APMV-3).

Variability of antigenic epitopes of the fusion protein of Newcastle disease virus.

Using a panel of 10 monoclonal antibodies (Mab) against fusion (F) protein of Newcastle disease virus (NDV), strain Australia-Victoria, three non-overlapping antigenic sites (F1, F2 and F3) and one site partially overlapping with the sites F1 and F2 (F1.2) have been identified. The sites F2 and F3 are clusters that each include four antigenic epitopes.

Mixed paramyxovirus infection of wild and domestic birds in Israel.

Five cases of dual isolations of different serotypes of avian paramyxoviruses (APMV) from domestic and wild birds are described: one case of mixed infection by APMV-1 and APMV-4 and four cases of infection by APMV-1 and APMV-2 serotypes. The double infection was proven by consecutive isolations of two viruses from allantoic fluid samples derived from single swabs after their respective treatment by antisera against each suspected virus. The finding of double APMV infection in poultry farms appears to be important for epizootiology and pathogenesis of APMV-caused diseases.

Antigenic epitope characterization of matrix protein of Newcastle disease virus using monoclonal antibody approach: contrasting variability amongst NDV strains.

A panel of 15 monoclonal antibodies (MABs) against matrix (M) protein of Newcastle disease virus (NDV) was obtained and the specificity towards the M protein was proven by radioimmunoprecipitation assay and antigen capture enzyme-linked immunosorbent assay (ELISA). Further studies were directed to antigenic epitope mapping of the M protein by means of this panel. The epitope characterization was performed by competitive antibody-binding assay by means of labelling each MAB with biotin [3].

Antigenic heterogeneity of avian paramyxoviruses of serotype 2 ("Yucaipa-like") isolated from domestic and wild birds in Israel.

Thirty-three viruses of PMV-2 serotype isolated in Israel from domestic and wild birds during epizooty of a respiratory disease in 1979-1981 were studied comprehensively in comparison with a set of reference PMV-2 viruses using cross reaction hemagglutination inhibition tests, elution-hemagglutination pattern and pattern of migration of viral proteins in polyacrylamide gel electrophoresis. The results demonstrated considerable heterogeneity amongst the local isolates by the above three criteria which were not correlated with each other. There was no significant correlation between the differences found and chronology of isolation of the viruses.

Antigenic heterogeneity of N2 neuraminidases of avian influenza viruses isolated in Israel.

Twenty one N2 neuraminidase (NA)-containing viruses isolated in Israel from different avian hosts during 1971-1984 were studied comparatively by means of the panel of 7 monoclonal antibodies (MAB) against A/Guiyang/57(H2N2) virus. Fifteen from the 21 viruses were studied in comprehensive cross reaction NA inhibition (NI) tests with the corresponding polyclonal antisera. The principal result of the studies is that all the isolates can be distributed into two main groups.

Effect of inhibitors of proteases and glycosidases on functional lability of newly synthesized hemagglutinin-neuraminidase glycoprotein in avirulent NDV strain-infected cells.

Inhibition of either glycosylation or the protein synthesis leads to sharp drop of hemagglutinating (HA) and neuraminidase (Nase) activities in Newcastle disease virus (NDV)-infected cells. The drop can be prevented by tosyl-lysyl-chloromethyl-ketone, an inhibitor of trypsin-like proteases, or D-galactonolactone, an inhibitor of glycosidases, if added together with cycloheximide. Tosyl-lysyl-chloromethyl-ketone when added alone increases the level of both the HA and Nase activities as compared with non-treated virus-infected cells.

The isolation of influenza virus from chickens in Israel and studies on its antigenic relationships with other native isolates of the same antigenicity by means of monoclonal antibodies.

A hemagglutinating (HA) agent isolated from an outbreak of a respiratory disease in a kibbutz broiler farm was identified as influenza virus A/chicken/Degania, Israel/80(H7N2). Investigation using a panel of 5 monoclonal antibodies against H7 antigenic subtype has shown substantial difference of the isolate from the other H7-containing influenza viruses isolated in Israel. Antigenic relationships between the native H7-containing strains revealed by means of the monoclonal antibodies led to re-evaluation of the suggested views on local epizootiology and interspecies transfer of avian influenza.

The first isolation of Newcastle disease virus (NDV) from free-flying birds in Israel: comparative studies on NDV strain isolated from migrating starlings (Sturnus vulgaris) wintering in Israel.

An NDV strain was isolated in Israel from a starling suffering from severe neurological affections. The strain appeared to be lentogenic to chickens, its hemagglutinin being thermostable and active toward horse erythrocytes. Comparative studies including LaSota and B1 NDV reference strains showed that the isolate is not a vaccinal strain used for vaccination in the country.

Isolation of a paramyxovirus from pigs in Israel and its antigenic relationships with avian paramyxoviruses.

During surveillance of the swine population in Israel a haemagglutinating agent was isolated and identified as a paramyxovirus (PMV). Serological studies based on haemagglutination and neuraminidase inhibition (HI and NI) tests displayed a close antigenic relationship between the isolate and the prototype strain of a variety of the avian PMV serotype 3 (PMV-3). However, comprehensive HI and NI cross-reaction tests between the isolate and PMV-3 reference strains, on the one hand, and the other eight avian PMV serotypes, on the other hand, showed that the viruses compared differed in terms of their antigenic interrelationships with the other avian PMVs and also in the quantitative values of the cross-reactivity.