The agency said veterinarians with the US Department of Agriculture (USDA) and WSDA visited numerous locations in quarantined areas and tested samples from several birds at those sites. All samples tested negative for avian influenza, WSDA added.
WSDA established the first quarantine on Jan. 29 in Riverside, Wash., and the second was set Feb. 2 in Oroville, Wash. The agency established a six-mile quarantine zone around a site in Riverside where avian influenza was confirmed in a flock of game birds. WSDA said that the avian influenza detected in the two Okanogan County flocks does not appear to have spread beyond those two sites. Both flocks were euthanized following detection of the disease, WSDA added.
Public health officials warned that exposure to avian influenza remains a possibility.
"Because migratory wild waterfowl can carry avian influenza, including highly-pathogenic avian influenza, WSDA continues to urge bird owners to protect their domestic birds from contact with wild waterfowl and remain vigilant in their biosecurity measures," the agency said in a statement.