Cause of Ocean Lake Waterfoul Die-Off Determined

Cause of Ocean Lake Waterfoul Die-Off Determined

LANDER — The Wyoming Game and Fish Department is releasing the lab results from a waterfowl die-off at Ocean Lake Wildlife Habitat Management Area that occurred in late November.

A total of 81 mallard ducks and one Canada goose were found afflicted and died.

At the Wyoming State Veterinary Laboratory, the Canada goose tested positive for highly pathogenic avian influenza (HPAI), however, the ducks did not. A full necropsy was performed and the ducks were found to have died from aspergillosis.

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Aspergillosis is primarily a respiratory disease where animals become infected by inhalation of fungal spores in the Aspergillus genus. These fungal spores occur naturally and grow in warm, moist decomposing organic matter, such as soil, grain, hay, and straw.

“Birds are especially susceptible to the disease and the severity of the lesions found in the lungs point to an incident where these ducks were exposed to a very acute and high dose of the spores,” said Game and Fish Wildlife Disease Specialist Jessica Jennings-Gaines.

“Aspergillosis is not typically a disease that causes major outbreaks by being spread from animal to animal,” Jennings-Gaines said. “We have seen a few cases around the state this fall, and it usually only affects those animals exposed to the source of the fungi. In contrast, HPAI does cause outbreaks as we have seen in birds this year and has hit geese and raptors particularly hard this fall and winter.” 

The Wyoming Game and Fish is investigating potential causes in the area, but the source may not be around any longer. No dead ducks or geese have been reported in any other area since the initial discovery.

Before the final diagnosis was made, the Game and Fish worked closely with the Department of Environmental Quality to examine all potential causes of the die-off that may have been related to the water or organic material in Ocean Lake.

The aerator at Ocean lake WHMA will be reinstalled and turned back on this week. 

No matter the disease of concern, it is always recommended to take precautions when handling wildlife and to follow the U.S. Fish and Wildlife Service’s general safety guidelines for hunters handling wildlife and their tissues:

  • Do not handle or eat sick game.
  • Field dress and prepare game outdoors or in a well-ventilated area.
  • Wear rubber or disposable nitrile gloves while handling or cleaning game.
  • When done handling game, wash hands thoroughly with soap or disinfectant and clean knives, equipment and surfaces that come in contact with game.
  • Do not eat, drink or smoke while handling animals.
  • Do not feed sick/found dead carcasses/tissues to domestic animals — such as dogs and cats.
  • All game should be thoroughly cooked to an internal temperature of 165 degrees F before being consumed.

The Wyoming Game and Fish Department reminds people to report clusters of dead birds online or to their nearest Game and Fish regional office.

You can find more information about aspergillosis here and HPAI here. If you have any questions, please call the Lander Regional Office at 307-332-2688.