Canada geese test positive for avian influenza at Iowa’s Green Valley Lake, Lake of Three Fires

H5 avian influenza has been confirmed in Canada geese at Green Valley Lake and at Lake of Three Fires, Iowa wildlife officials announced on Thursday.

Staff with the Iowa Department of Natural Resources (DNR) collected dead geese for testing at Iowa State University’s Veterinary Diagnostic Lab. Results were available late Wednesday.

Reports of dead geese at Green Valley Lake began on Dec. 11. Local staff began collecting geese off the ice but paused when weather conditions changed. As mild weather returned and the winds changed, the geese were more accessible and collection resumed.

So far, an estimated 60 geese have been collected at the popular southwest Iowa state park.

Local staff estimate thousands of geese are currently at Green Valley Lake as part of their fall migration. 

The Canada goose migration had increased across much of Iowa since the end of November with the onset of cold, snowy weather. The Iowa DNR’s December 12 waterfowl survey showed the Canada goose population increased more than 30% over the previous week as northern lakes and marshes froze and fields were covered in snow.

“We are getting reports of influenza activity across the western half of the state, and, for the first time, mass mortality events impacting southwest Iowa which has remained fairly insulated since 2022,” said Dr. Rachel Ruden, state wildlife veterinarian with the Iowa DNR.

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How long the outbreak will last is uncertain. As the rain and mild weather open up additional feeding and roosting locations, waterfowl will disperse which should reduce opportunities for transmission.

The public is encouraged to keep their distance from sick geese or those that are easily approached without obvious sign of injury. Also keep pets from interacting with sick or dead birds or consuming carcass parts.

While no human cases of H5 avian influenza have been linked to wild birds in the United States, there have been numerous cases linked to close contact with infected poultry and dairy cattle. Sick birds should not be handled or brought into shared living spaces.

Residents who see 20 or more carcasses in a small area are encouraged to call their local wildlife staff. Information is available online by visiting here, then scroll down to Wildlife Management Staff. Residents who find a single or a few birds can follow the steps for collection and disposal listed online here.

“We encourage the public to report sick birds or other wildlife to your local wildlife biologist or conservation officer to help us track impacts of this disease. We all have a part to play in keeping Iowa’s wildlife healthy,” said Dr. Ruden. 

Background

Avian influenza is a highly transmissible, naturally occurring virus found in certain waterfowl and shorebirds. There are various subtypes and strains, most of which cause limited harm to domestic poultry (low pathogenic) but some of which are lethal (highly pathogenic).

The H5N1 strain that has been circulating since 2022 is the first time HPAI has affected wild birds in North America at a large scale.

HPAI can also affect animals that consume infected carcasses, including other birds like hawks, and mammals, like red fox. The virus can remain viable in a deceased bird or contaminated water for several weeks, depending upon environmental conditions.

Information for Waterfowl Hunters

Waterfowl hunters can use these simple precautions to limit their exposure while field dressing and consuming wild game.

Cooking meat to an internal temperature of 165° F can kill the virus, if present. Additionally, please bag and dispose of offal and carcass parts to prevent exposure to scavengers.

While there is some inherent risk to hunting dogs given the nature of their interaction with carcasses, sick birds often become poor, uncoordinated flyers and so are less likely to be harvested. Hunters should prevent dogs from interacting with unknown carcasses, and avoid feeding them raw meat from harvested birds.

More information is available online.