H5N9 is a rare subtype of the influenza A virus that can cause highly pathogenic avian influenza (HPAI), also known as bird flu. It's a reassortment strain that originated from the H5N1, H7N9, and H9N2 subtypes.

A new strain of a highly pathogenic and rare strain of bird flu has been reported on a duck farm in central California.

The H5N1 virus has a ways to go before it can successfully jump to humans but that it doesn’t reduce the threat it poses.

The findings come at a time when outbreaks of bird flu -- a different subtype of the ... of the highly pathogenic avian influenza (HPAI) H5N1 influenza virus currently circulating

US officials are investigating the appearance of a strain of bird flu identified in the US for the first time, a worrying sign that the virus is evolving in ways that could make it harder to

H5N9 is a rare strain of avian influenza. H5N1 is the more ... "Whether this novel H5N9 virus will cause human infections from its avian host and become a pandemic subtype is not known yet.

U.S. authorities also detected the more common H5N1 strain on the same farm in Merced County, California, they said in a report to Paris-based WOAH, adding that the almost 119,000 birds on the

According to the Centers for Disease Control and Prevention, 67 people in the U.S. have been infected with H5N1 bird flu. One person has died.

The different, rarer sub-type of the common avian influenza H5N1 virus has been found on a duck farm in Merced County, California, according to the World Organization for Animal Health.

First U.S. detection of virulent H5N9 strain, at a California duck farm, draws scrutiny as evidence of genetic reassortment that could trigger human outbreaks.

The newly reported H5N9 strain was found Monday at a duck farm in Merced County, California, according to the World Organization for Animal Health. The Paris-based organization that studies animal diseases said it's the first verified U.S. case of H5N9 in poultry. The organization said the more common strain H5N1 was also found.