American infected with virus never seen before in humans
In this DML Report…
An older adult Washington state resident with underlying conditions was hospitalized in early November after contracting H5N5 bird flu, marking the first confirmed human infection with this strain, which had previously only been detected in animals. The patient presented with high fever, confusion, and severe breathing difficulties, initially receiving treatment in Grays Harbor County before transfer to a specialist facility in King County. Lab tests confirmed the H5N5 diagnosis, distinguishing it from prior human cases involving H5N1. This represents the first bird flu infection in the United States in at least eight months and the first in Washington state this year. Globally, 71 human cases of bird flu have been recorded since January 2022, with one death in Louisiana and only 4 cases detected in 2025.
The patient likely contracted the virus through exposure to a mixed backyard flock of domestic poultry and contact with wild birds, with two birds in the flock dying from an unidentified illness weeks prior; the remaining birds appear healthy. Infection could have occurred via bird saliva, droppings, or handling dead birds. The patient's contacts have been tested, with no additional cases identified as of Friday. The Washington State Department of Health announced the case during a press conference on Friday. Dr. Beth Lipton, Washington's public health veterinarian, stated that H5N5 is not an entirely new virus but the first known human infection. Virologist Dr. Angela Rasmussen noted the virus's unpredictable evolution and called for a thorough epidemiological investigation. Infectious diseases expert Dr. William Schaffner described the event as likely a rare one-off with no widespread public implications.
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Bird flu has been detected in every U.S. state since January 2022, affecting an estimated 174 million wild and domestic birds and over 1,000 dairy herds. Since September 2025, 7 million farmed birds have been impacted nationwide, including 1.3 million turkeys. Most human infections since 2022 have occurred in California (39 confirmed or probable cases) and Washington (15 confirmed or probable cases), often linked to domestic poultry or dairy cows. Infections are more common during wild bird migration periods. The CDC assesses the public risk as low, with no evidence that H5N5 is more infectious or severe than other strains, though concerns persist about potential adaptations for human-to-human transmission. The agency continues monitoring through flu surveillance systems and collaboration with states on exposures involving animals.