Avian Influenza Spreads Across Iowa

To paraphrase former U.S. President, Ronald Reagan, “Here we go again.”

A new wave of highly pathogenic avian influenza [HPAI] is currently sweeping across North America.  Similar to the outbreak which occurred during 2015, a Eurasian-origin strain of HPAI [commonly known as bird flu] was first detected in a captive, multi-species Canadian bird flock in December of 2021.  In January 2022, a U.S. Department of Agriculture [USDA] surveillance program discovered the pathogen in a hunter harvested American wigeon from South Carolina.  In February, the first outbreak in a commercial poultry [turkey] operation was reported in Indiana.  Since February, additional detections have been reported in commercial poultry flocks, backyard flocks, and wild bird populations across the U.S.

According to the USDA, avian influenza viruses are classified as either low pathogenic or highly pathogenic based on their genetic features and the severity of disease they cause in poultry.  Signs of infection include seizures, tremors, and respitory distress.  Domestic birds become symptomatic within 3 to 5 days of exposure to the virus.    

IOWA: In early March, the Iowa Department of Agriculture and Land Stewardship announced the first detection of highly pathogenic [H5N1] influenza in a backyard poultry flock in Pottawattamie County.  By mid-March, HPAI was detected in northbound populations of lesser snow geese and Ross’ geese in Plymouth, Harrison, Monona, and Dickenson counties.

Although a wide spectrum of bird species may contract the virus, H5N1 is most prevalent in shorebirds and waterfowl, according to State Wildlife Veterinarian, Rachel Ruden.  As the virus continues to move westward across the nation, at least 16 waterfowl species including mallards, pintail, scaup, black ducks, green-winged teal, redheads, wood ducks, snow geese and Ross’ geese from several states are testing positive for HPAI.   

“We think light [snow & Ross’] geese introduced the virus to wild bird populations in Iowa,” says Ruden.  “And although they’ve shed the virus here, they are also taking it with them as they leave the state.  As we continue to progress through the spring and summer seasons, we will no longer have those levels of disease influx entering the landscape.”

Although upland populations of pheasants, quail, turkeys, and other birdlife could also be suspectable to the virus, upland species occupy very different habitats than waterfowl.  Consequently, wildlife biologists anticipate minimal exposure for those species and — as occurred during the 2015 outbreak — it is hoped the virus will decrease as the seasons progress.

Contracting the bird flu is not necessarily a death sentence for waterfowl, says Ruden.  Ducks and geese may carry the disease and shed the virus without showing symptoms and may develop immunity.  By contrast, some bird groups are far less resistant.  Raptors have an extremely low tolerance to avian influenza.  Although mortality for hawks, owls, and eagles may be at or near 100 percent, bird flu victims that succumb in closed woodland habitats are less visible and less reported than wildfowl dying in more open, wetland environments. 

There are exceptions, of course.  On March 31, a sick red-tailed hawk was reported at Mason City in Cerro Gordo County.  Upon capture, the bird tested positive for H5N1, making it the first raptor known to have contracted the virus during Iowa’s latest outbreak.  Although no one can say how the hawk contracted the disease, biologists speculate it may have become infected after capturing and feeding on a bird already impaired or dying from the virus.

Because raptors such as bald eagles, red-shouldered hawks, and peregrine falcons frequent the same wetland habitats as waterfowl, these species may be at greater risk than other winged hunters.  Peregrines commonly prey on shorebirds, teal and other marsh birds; bald eagles frequently scavenge on dead or dying waterfowl resulting in potentially increased exposure during an avian virus outbreak.

Although HPAI is not easily transmitted to humans, it is bad news when it does.  In southeast Asia, the mortality rate for human poultry workers contracting the disease has exceeded 50 percent.  There have been no cases of HPAI infection in humans in North America and, according to the Centers for Disease Control and Prevention, the public is at low risk for infection.  Nevertheless, all suspect birds should be handled with caution.  Protocols for handling carcasses or birds displaying signs of illness should include the use of rubber gloves, masks, safety glasses or goggles, and disinfectants.  During cool spring weather, avian flu viruses may survive in bird carcasses for days or weeks. 

Although freezing bird carcasses does not kill the virus, outdoor enthusiasts may continue to safely consume ducks, geese, and other wild gamebirds.  Proper food preparation will eliminate all danger should a hunter unknowingly bag a bird already harboring the virus.  Cooking wild birds to an internal temperature of 165 degrees Fahrenheit will completely destroy all virus.

“This outbreak has our attention, and we want to effectively remove any birds showing symptoms of the virus,” says Ruden.  “We definitely want people to report dead birds or those showing signs of sickness.”

“What we’re telling people is this – “If you see something; say something”.

Sick or dead [wild] birds should be reported to local DNR wildlife biologists or DNR conservation officers.  Suspect domestic poultry should be directly reported to the Iowa Department of Agriculture and Land Stewardship at 515-281-5305.