Phylogenetic Diversity among Low-Virulence Newcastle Disease Viruses from Waterfowl and Shorebirds and Comparison of Genotype Distributions to Those of Poultry-Origin Isolates

Abstract

Low-virulence Newcastle disease viruses (loNDV) are frequently recovered from wild bird species, but little is known about their distribution, genetic diversity, or potential to cause disease in poultry. NDV isolates recovered from cloacal samples of apparently healthy waterfowl and shorebirds (WS) in the United States during 1986 to 2005 were examined for genomic diversity and their potential for virulence (n ‫؍‬ 249). In addition 19 loNDV isolates from U.S. live bird markets (LBMs) were analyzed and found to be genetically distinct from NDV used in live vaccines but related to WS-origin NDV. Phylogenetic analysis of the fusion protein identified nine novel genotypes among the class I NDV, and new genomic subgroups were identified among genotypes I and II of the class II viruses. The WS-origin viruses exhibited broad genetic and antigenic diversity, and some WS genotypes displayed a closer phylogenetic relationship to LBM-origin NDV. All NDV were predicted to be lentogenic based upon sequencing of the fusion cleavage site, intracerebral pathogenicity index, or mean death time in embryo assays. The USDA real-time reverse transcription-PCR assay, which targets the matrix gene, identified nearly all of the class II NDV tested but failed to detect class I viruses from both LBM and WS. The close phylogenetic proximity of some WS and LBM loNDV suggests that viral transmission may occur among wild birds and poultry; however, these events may occur unnoticed due to the broad genetic diversity of loNDV, the lentogenic presentation in birds, and the limitations of current rapid diagnostic tools.

Genotyping of Newcastle Disease Viruses Isolated from 2001 to 2007 in Japan

“…The isolate from the aigamo duck (JP/Hyogo-dk/02, which was isolated during surveillance) was classified into genotype I together with isolates mainly from waterfowl. This genotype I, has primarily been isolated from feral migratory waterfowl species, including mallards, baikal teals, and northern pintails in Far East Asia (Russia, Korea and Japan) [18] and North America (U.S.A.) [7].…”

Empirical analysis suggests continuous and homogeneous circulation of Newcastle disease virus in a wide range of wild bird species in Africa

“…Different LPNDV strains seem to commonly circulate in wild bird populations as illustrated by the phylogenetic diversity of LPNDV circulating in wild waterfowl and shorebirds in North America [9]. Regarding vNDV, some experimentally infected wild birds (e.g.…”

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“…The banding of the fusion gene amplicons was performed on Agarose gel, with expectation of its positioning at 254 bp [16]. The sequencing of the eluted amplicons was performed by using 3500 Avant Genetic Analyzer-ABI PRISM (Applied Biosystems, Hitachi), aiming at revealing the genotype of the v-NDV [9,10] and the uncovering of the structure of its cleavage site motif. The field experimental design in Part I of this research included 10 open-system broiler farms, located in the endemic area of v-NDV of genotype VI (34.5440° N, 36.0798° E.), with recurrent history of Newcastle disease outbreaks.…”