Pathogenicity evaluation of different Newcastle disease virus chimeras in 4-week-old chickens

Trop Anim Health Prod. 2010 Dec;42(8):1785-95. doi: 10.1007/s11250-010-9638-7. Epub 2010 Jul 8.

Abstract

The aim of this study was to evaluate the disease-inducing ability of four chimeric Newcastle disease viruses (NDV) by clinicopathological assessment. The infectious clones were previously generated by insertion of hemagglutinin-neuraminidase (HN) and/or fusion (F) genes from virulent strains (Turkey North Dakota and California 02) into a mesogenic strain (Anhinga) backbone. Groups of 4-week-old chickens were inoculated via eye drop instillation, clinical signs were monitored daily, and necropsies with collection of tissues were performed at 2, 5, 10, and 14 days post infection. Tissue sections were evaluated for histopathology and immunohistochemistry for NDV nucleoprotein. All viruses replicated successfully in the natural host, although viral recovery, seroconversion, and extent of immunohistochemical staining were greatest from birds infected with those viruses containing both F and HN genes from the same virulent virus. There was minimal to no increase in clinicopathologic disease due to infection with the chimeras compared to the recombinant backbone. However, all birds developed histological evidence of encephalitis. The results suggest that the inherent virulence of Turkey North Dakota and California 2002 strains is due to more than the simple presence of their F and HN genes.

MeSH terms

  • Animals
  • Chickens*
  • DNA Primers / genetics
  • Hemagglutinins, Viral / genetics
  • Histological Techniques / veterinary
  • Immunohistochemistry / veterinary
  • Neuraminidase / genetics
  • Newcastle Disease / pathology
  • Newcastle Disease / virology*
  • Newcastle disease virus / pathogenicity*
  • Nucleoproteins / metabolism
  • Poultry Diseases / pathology
  • Poultry Diseases / virology*
  • Reverse Transcriptase Polymerase Chain Reaction / veterinary
  • Serologic Tests / veterinary
  • Time Factors
  • Viral Fusion Proteins / genetics
  • Viral Fusion Proteins / metabolism*
  • Viral Proteins / metabolism

Substances

  • DNA Primers
  • Hemagglutinins, Viral
  • Nucleoproteins
  • Viral Fusion Proteins
  • Viral Proteins
  • nucleoprotein, Newcastle disease virus
  • Neuraminidase