Submitted to: Avian Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/3/2006
Publication Date: 4/6/2007
Citation: Lee, C.W., Lee, Y.J., Swayne, D.E., Senne, D., Linares, J., Suarez, D.L. 2007. Assessing potential pathogenicity of avian influenza virus: current and experimental system. Avian Diseases. 51:260-263. Interpretive Summary: Avian influenza virus can infect and cause a wide range of disease in poultry, including chickens and turkeys. The most severe form of the disease is referred to as highly pathogenic avian influenza. The highly pathogenic form of the virus is usually rare, having occurred only 5 times in North America in the last 25 years. However when outbreaks occur, they not only cause severe losses to disease and eradication costs, but it also disrupts poultry exports which is costs the poultry industry large sums of money. In some cases the virus has been reported to be highly pathogenic when in experimental studies it does not make birds sick. This study looks to assess why these differences occur and suggest that we need to evaluate our criteria for highly pathogenic avian influenza.
Technical Abstract: The current definition of high pathogenicity avian influenza (HPAI) virus includes potentially pathogenic viruses regardless of their pathogenicity in chickens. However, discordant results between the molecular classification, derived by sequencing the hemagglutinin cleavage site, and virulence for experimentally infected chickens have been observed with several H5 and H7 subtype AI viruses. Because the declaration of HPAI virus results in severe effects on trade for the entire country, the gap between the genetic and phenotypic markers is an important issue and it requires us to reexamine what should be considered a HPAI virus by the OIE standards. To better understand and assess the potential pathogenicity of the virus, potential pathogenicity of several AI virus isolates has been assessed by examining the plaquing efficiency of the virus in chicken embryo fibroblast cells, conducting 14-day-old embryo passage and selection system, and applying in-vitro mutagenesis coupled with reverse genetics. The potential value of those complimentary methods in assessing potential pathogenicity of the AI virus is discussed.