Overview
- University of Washington virology testing identified the virus as H5N5 and the CDC confirmed it, marking the first human infection with this subtype worldwide.
- The patient was an older adult from Grays Harbor County with underlying conditions who had been hospitalized in King County since early November and died on Nov. 21.
- State sampling detected avian influenza in the environment of the patient’s backyard flock, indicating exposure to domestic poultry, their surroundings, or visiting wild birds as the probable source.
- More than 100 healthcare workers and close contacts are being monitored, no additional infections have been found, and health authorities assess the public risk as low.
- Genetic analysis links the virus to H5N5 strains detected in eastern Canada, and the case occurs within a broader U.S. H5 outbreak that has seen about 71 human infections, mostly H5N1.