First Human Infection of Novel Bird Flu Strain Confirmed in Washington
Health officials in Washington state have confirmed that a resident has been hospitalised and is severely ill with a strain of bird flu previously undetected in humans. The patient, an older adult with underlying health conditions, was admitted in early November after experiencing a high fever, confusion, and significant breathing difficulties.
Details of the Case and Public Health Response
The individual was initially treated by doctors in Grays Harbor County, approximately 100 miles west of Seattle, before being transferred to a specialist care facility in King County. Laboratory tests subsequently confirmed the infection was caused by the H5N5 strain of avian influenza. While this strain has been identified in animals, this marks the first recorded human case globally. All previous human cases, where the strain was determined, were linked to H5N1.
Officials revealed the patient owns a mixed backyard flock of domestic poultry and had contact with wild birds prior to falling ill. Two birds from their flock died from an unidentified illness several weeks ago, though the rest currently remain healthy. The likely transmission route is exposure to saliva, droppings, or handling the body of an infected bird.
There is no current evidence that H5N5 is more infectious or causes more severe disease in humans than other bird flu strains. Health authorities have followed up with contacts of the patient and tested symptomatic individuals. As of last Friday, no further cases have been detected.
Expert Analysis and National Context
This case is the first bird flu infection detected in the United States in at least eight months and the first in Washington state this year. Since the outbreak began in January 2022, the US has recorded 71 human infections and one death. Only four cases have been identified in 2024.
Experts have emphasised the unpredictable nature of the virus. Dr Angela Rasmussen, a virologist, warned on social media platform X that the emergence of H5N5 in a human, resulting in hospitalisation, demonstrates the virus's capacity for unpredictable evolution. However, Dr William Schaffner, an infectious diseases specialist, suggested this is likely a 'rare one-off event' with limited implications for the general public.
Dr Beth Lipton, Washington's public health veterinarian, sought to reassure the public, stating, '[H5N5] is not a new strain or completely new virus. It is just the first time we know of that it has infected a person.' The Centers for Disease Control and Prevention (CDC) maintains that the current risk to the public from bird flu is low.
