 It is an HPAI (High Pathogenic Avian Influenza) virus, meaning that it can kill a very high percentage of chickens in a flock in mere days.It is believed to be the immediate precursor of the current dominant strain of HPAI A(H5N1) that evolved from 1999 to 2002 creating the Z genotype (also called "Asian lineage HPAI A(H5N1)") that is spreading globally and is epizootic (an epidemic in nonhumans) and panzootic (affecting animals of many species, especially over a wide area), killing tens of millions of birds and spurring the culling of hundreds of millions of others to stem its spread.The conversion to the Z genotype probably occurred by reassortment with a teal (duck) virus H6N1 during a mixed influenza infection