Chinese authorities first reported the A(H5N6) influenza virus in poultry in April. Since then, Laos and Vietnam have also detected the strain in domestic birds.
"Influenza viruses are constantly mixing and recombining to form new threats," said the FAO's chief veterinary officer, Juan Lubroth.
"However, H5N6 is particularly worrisome, since it has been detected in several places so far from one another, and because it is so highly pathogenic, meaning infected poultry quickly become sick and, within 72 hours, death rates are very high."
The fact that the virus is so highly virulent in chickens and geese and could potentially spread across large parts of Southeast Asia translates into a real threat to the millions in the region with livelihoods in the poultry industry.
Limited human threat
The World Organisation for Animal Health (OIE), which works together with FAO and the World Health Organisation (WHO) to support countries' responses to animal and human disease threats, is also monitoring the situation closely.
"An effective surveillance and an early detection of animal disease at source are two main keys to reduce the risk of dissemination and to ensure safe trade. The OIE calls on its 180 member countries to respect their commitment and to immediately notify of any outbreak detected on their territory," said OIE director-general Bernard Vallat.
Only one case of H5N6 has been reported in humans after contact with poultry shortly after its detection in China. The person later died, but there have been no other human cases.
Though the scientific community is still in the process of understanding the dynamics of this new strain, it is unlikely that H5N6 represents an immediate and significant threat to human health.
"Current evidence suggests H5N6 poses a limited threat to human health at this stage," said WHO epidemiologist Elizabeth Mumford.
"It's been detected in multiple places in poultry, yet we only have one human infection reported. This suggests that the virus does not easily jump from animals to humans. Of course, we still need to remain vigilant, because prevalence in poultry and therefore human exposure could increase during the winter."
Ramp up efforts
Even if the public health risks posed by H5N6 currently appears to be low, other pathogens, including other subtypes of influenza viruses such as H5N1 and H7N9, still can present cause for concern.
However, both the FAO and WHO have stressed that at this time it is critical for countries in Southeast and East Asia—and especially those with links to poultry production and trade—to ramp up efforts to detect and report influenza viruses in poultry and monitor for any human infections.
An H5N6 outbreak could potentially overwhelm animal health systems in Southeast Asia, the FAO warned. An earlier strain of the virus, H5N1, has already impacted the livelihoods of millions of people and caused billions of dollars of damage.