Bulgaria reported an outbreak of highly pathogenic avian influenza among poultry, the World Organisation for Animal Health (WOAH) said on Friday, as Europe faces a seasonal upturn in the deadly disease.

Bird flu has infected a commercial flock of about 800,000 fowl at an egg farm in southeast Washington, the state’s Department of Agriculture said this week. It’s the first detection in Washington this year of highly pathogenic avian influenza in a commercial poultry operation and is one of about four dozen known commercial and domestic

Concerns about bird flu — officially known as avian influenza A (H5) — continue to mount, particularly in California. Infectious disease experts voice their concerns and recommend precautions.