SALMON, Idaho — Idaho state and federal officials say they have received indication that over 100 mallard ducks near Salmon died of an acute fungal infection. Idaho Fish and Games says the cause of death is almost certainly acute Aspergillosis.
Aspergillosis is a respiratory tract infection caused by a fungus found in soil, dead leave, moldy grain, compost piles or in other decaying vegetation. Fungal cultures in two of three ducks tested showed growth of Aspergillus fungi.
IDFG says final confirmation is pending according to the most recent update from the National Wildlife Health Center in Madison, Wisconsin. The fungus can cause severe respiratory tract infections in birds that inhale the spores but it cannot be passed from one infected duck to another.
"We are fortunate that the die-off seems to have stopped, likely due to the fungus source no longer being available to the ducks,” said Dennis Newman, Idaho Fish and Game wildlife manager based in Salmon.
The disease is not contagious to humans who eat the meat, but hunters can be exposed by inhaling spores from contaminated carcasses. IDFG says the risk of exposure is minimal but suggests hunters wear masks when dressing their birds. As with all game, hunters should also wear latex gloves when field dressing and the meat should be thoroughly cooked.
The first dead ducks were reported on December 7 south of Salmon. IDFG responded and found 50 ducks along an irrigation ditch and in sloughs and ponds. Since then, IDFG has found 115 dead ducks.
While it is a small proportion of the duck population, the number is unusual for the area, according to IDFG. Waterfowl die-offs are common and happen every year. Testing for diseases is a routine part of the investigation of waterfowl die-offs.
Tissue samples from the dead birds were not consistent with avian influenza, but as a precaution, samples are continuing to undergo further testing to confirm Aspergillosis and rule out any potential underlying disease. Results from these tests are pending.