Submitted to: National Poultry Improvement Plan Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 9, 2004
Publication Date: July 9, 2004
Citation: Spackman, E. 2004. Does Low Pathogenicity H5 and H7 Avian Influenza Pose A Threat? National Poultry Improvement Plan Meeting, 07/09/2004. Technical Abstract: Avian influenza is classified as either low pathogenic (LP) or highly pathogenic (HP) based on the ability of the virus to cause mortality in susceptible chickens. Of the 15 Hemagglutinin subtypes of avian influenza only the H5 and H7 subtypes have been HP. Although most H5 and H7 avian influenza viruses are LP, when they circulate in chickens they can mutate into the HP form of the virus. There is no clear reason why this may occur; it can not be predicted. However the biological mechanism responsible for a virus being HP versus LP is known. The mechanism for the shift of LP to HP avian influenza will be discussed in the context of historical avian influenza outbreaks in chickens where this is believed to have occurred.