Yesterday (January 20th) there were several media mentions of HPAI H5 detected in Idaho – the fifth US state to report these emerging avian viruses since early December.
Crof picked up a story (see US: Highly pathogenic bird flu strikes Idaho for first time), and Lisa Schnirring of CIDRAP NEWS referenced it last night in her excellent roundup Tests reveal H5N1 in Israeli turkeys, four countries report other strains.
Idaho – like many of our western states - lies beneath the Pacific Migratory Flyway (see below), which runs north-south from Siberia to the tip of South America.
While most flyways are north-south, their overlapping allows for a lateral (east-west) movement of avian viruses as well – often via shared nesting areas and ponds – something we’ve looked at recently in The North Atlantic Flyway Revisited & FAO On The Potential Threat Of HPAI Spread Via Migratory Birds.
This year we’ve seen an unprecedented global spread of HPAI H5 viruses (primarily H5N8 & H5N2), with viruses appearing only recently in Korea and Eastern China now showing up in Europe and North America, apparently carried by migratory birds.
Luckily neither of these two subtypes is currently viewed as posing a serious threat to human health, although they can be devastating to poultry operations. The concern – beyond its considerable threat to the poultry industry – is that these viruses can meet up with other influenza viruses and reassort –potentially producing hybrid strains - possibly with unpredictable results.
Shift, or reassortment, happens when two different influenza viruses co-infect the same host swap genetic material. New hybrid viruses may be the result of multiple reassortments, with gene contributions coming from several parental viruses. Recently we’ve seen reports of two new reassortments with imported HPAI H5 in Taiwan, resulting in a `new’ H5N2 and a `new’ H5N3’ virus.
Boise – The Idaho State Department of Agriculture (ISDA) has initiated a multi-agency investigation following the confirmation of a highly pathogenic strain of the avian influenza virus (HPAI), originating from wild waterfowl, in western and southern Idaho. The incidents of HPAI recently found in Washington, Oregon, California and Utah, led USDA Wildlife Services and the Idaho Department of Fish and Game to increase routine disease surveillance of wild waterfowl in common migratory regions of Idaho.
Surveillance conducted in Gooding County identified several cases of H5N8 avian influenza in wild ducks. The H5N2 strain of avian influenza virus was confirmed in three falcons from a private, noncommercial flock in Canyon County, Idaho and was a result of recent contact with wild waterfowl. The flock is currently under quarantine and additional viral testing is being conducted on the remaining birds.
Additionally, a small backyard poultry flock in Canyon County, Idaho was identified as having chickens positive for H5N2. That flock was immediately put under quarantine and the birds have been depopulated.
“Both the H5N8 and H5N2 strains of HPAI confirmed in Idaho have previously been identified in incidents in backyard domestic poultry and wild fowl in other northwestern states. It is critical that backyard flock owners and poultry producers take every opportunity to prevent contact between domestic birds and the wild waterfowl that carry the avian influenza virus” said Dr. Bill Barton, ISDA State Veterinarian.
The ISDA is working closely with the Idaho Department of Fish and Game, the Idaho Department of Health and Welfare, USDA APHIS Wildlife Services and USDA APHIS Veterinary Services to further disease surveillance for avian influenza, statewide.
There have been no human illnesses associated with the H5N8 or H5N2 viral strains of avian influenza anywhere in the world, to date. The virus has not been found in commercial poultry anywhere in the United States.
However, to reduce the risk of exposure, individuals handling wild and domestic birds should remember to wash their hands after contact and cook all poultry and poultry products thoroughly prior to consumption. ISDA encourages commercial poultry growers and backyard owners to be vigilant with biosecurity measures, including maintaining separation between their flocks (including all feed and watering sites) and any wild birds.
All poultry producers should monitor their flocks for signs of illness in their birds. Symptoms of avian influenza include, but are not limited to, coughing, sneezing, respiratory distress, decreased egg production, swelling of the head, comb and wattles and sudden death. If producers observe symptoms consistent with HPAI in any of their birds, please contact the ISDA State Veterinarian’s office at 208-332-8540 or USDA-APHIS-VS, toll free at 1 -866-536-7593. Sick or dead wild birds should be reported to the Idaho Department of Fish & Game at 208-454-7638. Additional information about avian influenza and updates in the Idaho bird cases can be found at www.agri.idaho.gov under “Quick References – Avian Influenza Information”.
Additional information on seasonal and avian influenza in humans can be found at http://flu.idaho.gov . Information on Hunter Health can be found at
http://www.healthandwelfare.idaho.gov/Health/HunterHealth/tabid/1280/Default.aspx # # # USDA brochure – What is Avian Influenza?
http://www.aphis.usda.gov/wildlife_damage/nwdp/pdf/AvianFluBrochure.pdf Information on biosecurity (keeping birds healthy) for backyard flocks
http://healthybirds.aphis.usda.gov/ Video from USDA – Simple Steps to Keep Backyard Poultry Healthy
45 Video en espanol from USDA - Medidas Sencillas Para Mantener Saludables a Sus Aves de Corral
Given the apparent ease by which these two HPAI H5 viruses are hitching rides on wild and migratory birds, one shouldn’t be terribly surprised to see reports from additional states, and perhaps even from regions south of the US border.