Archives of Virology

, Volume 156, Issue 1, pp 37–51 | Cite as

Pathogenicity of two Egyptian H5N1 highly pathogenic avian influenza viruses in domestic ducks

  • J. L. Wasilenko
  • A. M. Arafa
  • A. A. Selim
  • M. K. Hassan
  • M. M. Aly
  • A. Ali
  • S. Nassif
  • E. Elebiary
  • A. Balish
  • A. Klimov
  • D. L. Suarez
  • D. E. Swayne
  • M. J. Pantin-Jackwood
Original Article

Abstract

Domestic ducks have been implicated in the dissemination and evolution of H5N1 highly pathogenic avian influenza (HPAI) viruses. In this study, two H5N1 HPAI viruses belonging to clade 2.2.1 isolated in Egypt in 2007 and 2008 were analyzed for their pathogenicity in domestic Pekin ducks. Both viruses produced clinical signs and mortality, but the 2008 virus was more virulent, inducing early onset of neurological signs and killing all ducks with a mean death time (MDT) of 4.1 days. The 2007 virus killed 3/8 ducks with a MDT of 7 days. Full-genome sequencing and phylogenetic analysis were used to examine differences in the virus genes that might explain the differences observed in pathogenicity. The genomes differed in 49 amino acids, with most of the differences found in the hemagglutinin protein. This increase in pathogenicity in ducks observed with certain H5N1 HPAI viruses has implications for the control of the disease, since vaccinated ducks infected with highly virulent strains shed viruses for longer periods of time, perpetuating the virus in the environment and increasing the possibility of transmission to susceptible birds.

Notes

Acknowledgments

The authors appreciate the assistance provided by Diane Smith, Ronald Graham and Roger Brock in conducting these studies. The authors also thank the SAA sequencing facility at SEPRL and the FSIS histopathology laboratory at Russell Research Center-USDA for technical assistance. They also thank the Naval Medical Research Unit No. 3 (NAMRU3), Egypt, for help providing one of the viruses. Funding was given by the US Department of Agriculture, ARS, Current Research Information System project #6612-32000-048.

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Copyright information

© US Government 2010

Authors and Affiliations

  • J. L. Wasilenko
    • 1
  • A. M. Arafa
    • 2
  • A. A. Selim
    • 2
  • M. K. Hassan
    • 2
  • M. M. Aly
    • 2
  • A. Ali
    • 3
  • S. Nassif
    • 3
  • E. Elebiary
    • 3
  • A. Balish
    • 4
  • A. Klimov
    • 4
  • D. L. Suarez
    • 1
  • D. E. Swayne
    • 1
  • M. J. Pantin-Jackwood
    • 1
  1. 1.Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research LaboratoryUnited States Department of Agriculture, Agricultural Research ServiceAthensUSA
  2. 2.National Laboratory for Veterinary Quality Control on Poultry ProductionGizaEgypt
  3. 3.Central Laboratory for Evaluation of Veterinary Biologics (CLEVB)CairoEgypt
  4. 4.Influenza DivisionNational Center for Immunization and Respiratory Diseases, Centers for Disease Control and PreventionAtlantaUSA

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