On Jun. 10, 2022, the U.S. Department of Agriculture’s (USDA) National Veterinary Services Laboratory (NVSL) confirmed the presence of highly pathogenic avian influenza (HPAI) in a backyard flock of duck and geese in Polk County, Oregon.

The flock’s owner notified a private veterinarian after the sudden death of at least one bird; meanwhile, other birds in the flock were displaying clinical signs consistent with HPAI.

The veterinarian sent a sample of the deceased bird to Oregon State University in Corvallis. A preliminary test came back positive for HPAI. NVSL made the official confirmation on June 9.

HPAI is a highly contagious virus that transmits easily among wild and domestic bird species. Symptoms include diarrhea, incoordination, lethargy, coughing and sneezing, and sudden death, although birds infected with HPAI may not always display outward signs of infection.

The virus may spread in various ways, including through contact with infected wild and domestic birds and by contaminated equipment, clothing, and shoes of caretakers. The affected backyard flock in Polk County was known to co-mingle with wild birds at a nearby pond.