| Avian Paramyxovirus consisted of nine serotypes, APMV 1-9, but APMV-1 only included Newcastle disease virus. There existed tremendous virulence diversity among different hosts in which chicken was the most sensitive, pigeon and parrot also could be infected and falled ill. Waterfowls such as geese or ducks constantly were not considered to be infected by NDV. For the past few years, uninterruptly expanding of the host infection spectrum about NDV, chicken, pigeon, parrot and some rare birds could be infected, as well as waterfowls. The outbreak of goose-host paramyxovirus disease broken traditionary theory which said waterfowls could not be infected by NDV. However, since 1999, researchers isolated paramyxovirus from swine. After studying the virus is the variation of NDV strains that are infected the mammals (swine).In this study, our lab isolated NDV from illed swines in 2005, named JL-1. Electron microscopy revealed the morphology of a paramyxovirus. Hemagglutination and hemagglutination inhibition tests confirmed the JL-1 and APMV-1 have the relationship between the serum. Through MDT, EID50, ICPI, IVPI tests determind that JL-1 is avirulent. After molecular identification confirm the porcine paramyxovirus strain JL-1 is the Newcastle disease virus variant. Cloning and sequence analysis of the F protein found that the encoding F protein cleavage site amino acid composition for the 112-G-R-Q-G-R-L-117, which is characteristics of avirulent, that confirm the JL-1 is avirulent in molecular level again, LaSota, and homology of 99.5%, belong to F typeⅡgene. To confirmed virus origin taxonomic status and the source of the porcine paramyxovirus strain JL-1. A total of ten overlapping cDNA clones, covering the entire genome of JL-1, were obtained by either target gene walking RT-PCR or 5'- and 3'-RACE. The genomes of nine NDV strains including Aus/32, Beaudette C, Herts/33, LaSota, Ulster, HB92 V4, SF02, ZJ1 and NA-1 were compared to the nucleotide sequence of the gene of strain JL-1. JL-1 was isolated from swine; NA-1, SF02 and ZJ1 were all isolated from geese, others from chicken. The results showed that NP nucleotide homology of 85.37% - 99.32%; P nucleotide homology of 82.66% - 99.92%; M nucleotide homology of 84.84% - 99.82%; F nucleotide homology 84.60 % - 99.52; HN nucleotide homology of 81.66% - 100%; L nucleotide homology of 86.20% - 99.83%; 5'nucleotide homology of 60.2% - 99.1%; 3'nucleotide homology of 85.5% - 100%. The results showed that JL-1 strains was closely related to the LaSota, Beaudette C strain, with higher nucleotide homology, but low nucleotide homology with geese NDV。Sequence compiled from these clones showed that the genome of strain JL-1 was 15,021 nt long (GenBank accession # EU546165). Analysis of sequence shown that JL-1 had changed in 1590-1798 nt, 1821-1894 nt, 2298-2418 nt, 3091-3263 nt, 4418-4670 nt, 15010-15090 nt. That confirmed infect swine is the Newcastle disease virus variant first. Phylogeny of JL-1 showed that it is the same evolutionary branch with LaSota, Beaudette C, and Clone 30. It revealed NDV has infected mammal (swine). This study provide a theoretical basis for the origin and prevalence characteristics of porcine paramyxovirus, and had founded basic for the reasons for change that Characteristics of infected host and the molecular mechanism change of NDV specificity host.
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