Major Global Migratory Flyways – Credit FAO
Although they are but skirmishes at this point, the USDA, APHIS, and state and local agriculture officials – along with the poultry industry – continue to battle the recent importation (via migratory birds) of highly pathogenic avian influenza (HPAI) in the western United States.
First a statement on the latest find from the Oregon Department of Agriculture, after which I’ll be back with a bit more:
February 14th, 2015
The Oregon Department of Agriculture, in cooperation with the US Department of Agriculture, is responding to a detection of highly pathogenic avian influenza (HPAI) in a flock of backyard birds near Tumalo in Deschutes County. ODA, working with the USDA’s Animal Health Inspection Service (APHIS), is in the process of setting up a quarantine zone around the property to restrict movement of domestic birds in and out of the area. Currently, the property is secured and there have been no additional detections of HPAI in the area.
The flock of about 90 mixed poultry and other domestic birds includes chickens, ducks, and turkeys that have had access to a couple of ponds on the property that are also frequented by migratory wild waterfowl. Avian influenza naturally resides in wild birds and it is fairly common for waterfowl to carry various strains of the virus. HPAI has also been reported in backyard birds in Washington and Idaho, and in wild birds in all three Pacific Northwest states.
The Deschutes County detection is the second in Oregon. HPAI was detected in a flock of backyard birds in Douglas County in December.
Until a few months ago North American poultry producers had little to fear over the Asian HPAI H5 viruses like H5N1, or the recently emerged H5N8 which has wreaked havoc in Korea and Taiwan. While North American birds carry many different LPAI (low pathogenic) viruses, the really dangerous ones were thousands of miles and an ocean away.
But time, overlapping migratory flyways, and a newly emerged HPAI H5 that seems particularly well suited for carriage by wild and migratory birds have combined to bring H5N8, and its reassortant H5N2 and H5N1 offspring, to the Americas.
Suddenly the bird flu problem which has plagued Asian and Middle Eastern poultry produces has come here to roost, putting poultry operations from Canada to Mexico on alert. Thus far these HPAI viruses have only affected one commercial operation in the United States, and about a dozen in Canada, but they continue to crop up in wild and migratory birds and a handful of backyard flocks.
The USDA’s National Veterinary Services Laboratories confirmed Wild Bird Findings are now at 30 cases, and climbing.
Our knowledge of how these new reassortant viruses will behave in poultry, and in humans, is very limited at this time. Other reassortants carrying this H5 gene segment (H5N8, H5N2) have not yet been shown to pose a health risk to humans.
Whether that will hold true with these viruses remains to be seen.
For now the CDC is taking a cautious approach to all of of these recently arrived HPAI viruses, and has issued guidance for the testing, and prophylactic treatment of those exposed.
And local and state officials are asking people report, but not touch, dead birds.