ABSTRACT
Low pathogenicity avian influenza (H5N2) virus was detected in poultry in the Dominican Republic in 2007 and re-emerged in 2017. Whole-genome sequencing and phylogenetic analysis show introduction of an H5N2 virus lineage from Mexico into poultry in the Dominican Republic, then divergence into 3 distinct genetic subgroups during 2007-2019.
Subject(s)
Influenza A Virus, H5N2 Subtype , Influenza in Birds , Poultry Diseases , Animals , Dominican Republic/epidemiology , Influenza in Birds/epidemiology , Mexico , Phylogeny , Poultry , VirulenceABSTRACT
A Newcastle disease virus (NDV) outbreak in chickens was reported in the Dominican Republic in 2008. The complete genome of this isolate, chicken/DominicanRepublic(JuanLopez)/499-31/2008 (NDV-DR499-31/08), and the fusion proteins of three other related viruses from the Dominican Republic and Mexico were sequenced and phylogenetically analyzed. Genetically, these four isolates were highly distinct from all other currently known isolates of NDV, and together, they fulfill the newly established criteria for inclusion as a novel genotype of NDV (genotype XVI). The lack of any reported isolation of viruses related to this group since 1986 suggests that virulent viruses of this genotype may have evolved unnoticed for 22 years. The NDV-DR499-31/08 isolate had an intracerebral pathogenicity index (ICPI) score of 1.88, and sequencing of the fusion cleavage site identified multiple basic amino acids and a phenylalanine at position 117, indicating this isolate to be virulent. These results were further confirmed by a clinicopathological assessment in vivo. In 4-week-old chickens, NDV-DR499-31/08 behaved as a velogenic viscerotropic strain with systemic virus distribution and severe necrohemorrhagic lesions targeting mainly the intestine and the lymphoid organs. The clear phylogenetic relationship between the 2008, 1986, and 1947 ancestral viruses suggests that virulent NDV strains may have evolved in unknown reservoirs in the Caribbean and surrounding regions and underlines the importance of continued and improved epidemiological surveillance strategies to detect NDV in wild-bird species and commercial poultry.
Subject(s)
Evolution, Molecular , Genotype , Newcastle disease virus/genetics , Animals , Chickens , Genome, Viral , Newcastle Disease/pathology , Newcastle Disease/virology , Newcastle disease virus/classification , Newcastle disease virus/pathogenicity , Phenotype , Phylogeny , Poultry Diseases/virology , Viral Fusion Proteins/genetics , Virulence Factors/geneticsABSTRACT
Newcastle disease virus (NDV) was isolated from an outbreak in layer chickens in the Dominican Republic in 2008. Infections with this isolate led to a 100% apparent case fatality rate in birds. Complete genome sequencing revealed that the isolate does not belong to any of the previously described NDV genotypes. Similarly, large differences were observed in the amino acid sequence of the fusion and hemagglutinin-neuraminidase proteins in comparison with all known NDV genotypes, suggesting the existence of an unknown reservoir for NDV. The work presented here represents the first complete genome sequence of NDV in the Dominican Republic.
