A resident of Washington state is in the hospital with a critical case of bird flu, according to health officials. This individual contracted a strain of the virus, H5N5, that has never been observed in humans before.

The patient, described as an older adult with pre-existing health conditions, was admitted to the hospital in early November. They experienced symptoms such as a high fever, confusion, and severe respiratory distress, officials reported.

Initially treated in Grays Harbor County, located roughly 100 miles from Seattle, the patient was later moved to a hospital in King County for advanced medical care.

Laboratory tests identified the infection as H5N5, a subtype of avian influenza known in animals but not previously documented in human cases.

While most human cases of bird flu have involved the H5N1 strain, the emergence of H5N5 in a human underscores the virus’s unpredictable nature. However, experts note there is no current indication that this strain poses a greater risk of transmission or severity in humans compared to other strains.

This incident is the first bird flu infection reported in the United States in over eight months and the inaugural case in Washington state this year.

Since the bird flu outbreak began in January 2022, a total of 71 people have been infected, and one individual, a person in Louisiana, has died. Only four cases have been detected so far this year.

Officials have stressed, however, that the risk to the public remains low. Dr Beth Lipton, the state’s public health veterinarian, said in a press conference: ‘[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.’   

Officials in Washington state are warning over a new case of bird flu. Shown above is a worker in a Hazmat suit cleaning a truck in a quarantine zone after a bird flu outbreak in Victoria, Australia, in June last year 

Officials at the Washington State Department of Health revealed the infection with a new strain of the virus at a press conference on Friday.

Further details about the patient, including their name, gender, age, and treatment, were not revealed. 

It was not clear how the individual was infected, but officials said it was likely linked to exposure to wild or domestic birds.

The patient owns a mixed backyard flock of domestic poultry, officials said, and had contact with wild birds prior to their infection.

Two of the birds in their flock died from an unidentified illness a few weeks ago, although the rest of the birds currently remain healthy.

It is possible to become infected with the virus after being exposed to saliva or droppings from infected birds or handling the body of a bird that died from the virus.

Officials have followed up with individuals who had contact with the patient and tested those who had symptoms. There were no further cases of bird flu detected as of Friday, officials said.

The above map shows states with confirmed human infections with bird flu. All previous infections were due to the H5N1 strain

There is no current evidence that H5N5 is more likely to cause infections or severe disease in humans than other strains of bird flu

Dr Angela Rasmussen, a virologist in Canada, warned on X: ‘It’s not H5N1, it’s H5N5, but that isn’t a relief to me. It’s a reassortment that put someone in the hospital. This is unpredictable. 

‘I hope epidemiologists are investigating to assess who else might have been exposed, so appropriate outbreak investigation and control can be applied.’

Dr William Schaffner, an infectious diseases expert in Tennessee, told Newsweek: ‘Infection with H5N5 bird flu virus likely is a rare one-off event that does not have widespread implications for the general public.’ 

Since the bird flu outbreak began in 2022, most patients have been in either California, 39 confirmed or probable bird flu cases, or Washington, 15 confirmed or probable bird flu cases.

In most cases, infections have been linked either to exposure to infected domestic poultry or dairy cows, which have also been infected by the virus.

In wild and domestic birds, bird flu has now been detected in every state in the US since January 2022.

An estimated 174million wild and domestic birds are estimated to have been affected, while more than 1,000 dairy herds have also been infected.

Since September this year, it has struck 7million farmed birds nationwide including 1.3million turkeys, leading to concerns that there may be a shortage for thanksgiving. 

Experts warn that infections with bird flu are more common at this time of year because wild birds, which may be carrying the virus, migrate, potentially spreading the virus to new areas.

There remain concerns that the virus could spread to and learn how to spread between humans, which could spark a new outbreak similar to the Covid pandemic. 

The CDC says online that the risk to the public from bird flu remains low.

It says online: ‘H5 bird flu is widespread in wild birds worldwide and is causing outbreaks in poultry and US dairy cows with several recent human cases in US dairy and poultry workers.

‘While the current public health risk is low, CDC is watching the situation carefully and working with states to monitor people with animal exposures.

‘CDC is using its flu surveillance systems to monitor H5 bird flu actively in people.’