Although the USDA and APHIS have taken point in the battle against the entry of HPAI H5 into North American poultry, the USGS has a long history of studying wild and migratory birds, and the viruses they carry. They were the first to detect HPAI H5 in the United States last December (see EID Journal: Novel Eurasian HPAI A H5 Viruses in Wild Birds – Washington, USA), and are expected to be our best early warning system again this fall and winter.
Over the past 10 years we’ve looked at a number of USGS avian flu studies, including:
- In 2008, a USGS study found Genetic Evidence Of The Movement Of Avian Influenza Viruses From Asia To North America, that suggested migratory birds play a larger role in intercontinental spread of avian influenza viruses than previously thought.
- A couple of years later, in Where The Wild Duck Goes, we looked at a USGS program that used Satellite Tracking To Reveal How Wild Birds May Spread Avian Flu.
- In 2014, a USGS/NIAD funded study found the North Atlantic May Be a New Route for Spread of Avian Flu to North America
- And last April, in USGS: Alaska - A Hotspot For Eurasian Avian Flu Introductions we looked at a study that found evidence of the international spread of avian H9N2 from China and South Korea into North America.
While it may have taken more than 10 years for an HPAI H5 virus to finally make it into North America, for much of that time the USGS had been warning us of that very possibility.
Last night the USGS published an overview of their work to understand how HPAI viruses like H5N2 and H5N8 entered North America, and how they continue to evolve and spread. It is also a pretty good primer on the overall avian flu threat. Follow the link to read:
Highly pathogenic avian influenza (HPAI), commonly referred to as bird flu, is making its way across North America. In December 2014, the USGS detected three related HPAI H5 viruses in Washington state. To date, strains have been detected in wild birds in 14 states and commercial and backyard poultry in 15 states. Nine states have had outbreaks in both wild birds and poultry.
The USGS made the initial detection of HPAI in the United States in December 2014. This first detection was in a northern pintail duck from Washington State, like the bird pictured here.
“Low pathogenic avian influenza viruses usually start in wild birds and when they spread to domestic birds, they can mutate into the HPAI form,”said USGS avian influenza expert Hon Ip. “HPAI poses significant threats to commercial poultry and threatens agricultural trade.”
Influenza is a cunning virus, constantly evolving and mutating into different strains with varying risks to animal and human health. It travels with its bird or mammal host, sometimes over very long distances, sometimes even across oceans. Hitchhiking viruses from afar can mix with local strains to create novel types of flu, contributing to and further complicating the process of mutation.
Perplexed? You’re not alone. Unraveling the mysteries of HPAI is complex—baffling, even—but USGS wildlife disease investigators and their partners are taking on the challenge.
“Our avian flu surveillance is crucial for providing farmers and wildlife managers with early outbreak warnings to help protect valuable poultry, and for helping our partners best protect animal and human health,” said Jonathan Sleeman, director of the USGS National Wildlife Health Center (NWHC) in Madison, Wisconsin, which was instrumental in the first detection of these HPAI viruses in the United States.
While the health risk posed to the general public by these HPAI outbreaks is low at this time, it is possible that human infections with these viruses may occur, according to the Centers for Disease Control and Prevention (CDC).