A child in California has tested positive for bird flu, local health officials say — the first pediatric case — amid growing fears the disease could spread between humans.
The unidentified child suffered from mild respiratory symptoms and had attended daycare in Alameda county, part of the state’s Bay Area.
They have been isolated at home and are receiving treatment, with none of their family members or playmates testing positive for the H5N1 virus. Health officials are still investigating how they caught the virus.
Health officials say the risk to the public remains ‘low.’
But the case underscores the possibility bird flu could spread among people, after it caused an outbreak among cows in 2022 that sickened more than 500 herds and then jumped to humans.
It is the first reported case in a child in the US and at least the 53rd human case nationwide. The cases have mostly been linked to exposure to birds or cattle, but in one case an individual did not have contact with either.
And in Canada, a teenager with no contact with cows or birds is in a critical condition in the hospital after being diagnosed with bird flu.
All of the US patients reported mild symptoms — such as red eyes or mild respiratory symptoms — and none have died from the disease.
But CDC researchers said today many cases have likely slipped under the radar and are not being detected or reported.
In a study on blood samples from 115 dairy farm workers in Michigan and Colorado who had either tested negative for bird flu or had not been tested at all, the agency found seven percent — eight people — had antibodies against the virus.
PINK EYE: The H5N1 virus causes eye inflammation, as seen in a dairy farmer in Texas who caught bird flu earlier this year
While experts are concerned over missed cases, they are encouraged it means most people who contract the bird flu are not becoming severely ill.
However, the CDC warned each infection raised the risk of the virus gaining mutations to make it better able to spread between people and cause severe illness.
In California, health officials said the child had low levels of the virus in their positive test, suggesting they were not infectious to others.
A second test carried out four days later was negative, suggesting their body had fought off the infection.
It is not clear how the child became infected, but health officials said they were investigating a possible link to exposure to wild birds.
They tested positive for an H5 flu virus, with the sample being sent for confirmatory testing at the CDC to confirm H5N1, the strain of bird flu causing the outbreak in the US.
State health director Dr Tomas Aragon said: ‘It’s natural for people to be concerned, and we want to reinforce for parents, caregivers and families that based on the information and data we have, we don’t think the child was infectious.’
He added: ‘No human-to-human spread of bird flu has been documented in any country for more than 15 years.’
The above map shows the locations of bird flu infections in the US over 2024 and during the current outbreak. There have now been 27 confirmed cases of bird flu in California, with all having previously had mild symptoms
In the CDC study testing for antibodies in farmworkers’ blood, four of the participants said they remembered being ill around the same time the cows they worked with tested positive for bird flu.
All of the workers — who were tested between June and August this year — reported milking the cows or cleaning the milking parlor.
None of the workers that tested positive for bird flu antibodies had worn personal protective equipment (PPE) when working with infected cattle.
Overall, the use of PPE among the study participants was ‘low,’ the researchers said.
The CDC said in the study, published in its Morbidity and Mortality Weekly Reports: ‘This finding supports the need to identify and implement strategies to prevent transmission among dairy cattle to reduce worker exposures.
‘And for education and outreach to dairy workers concerning prevention, symptoms, and where to seek medical care if the workers develop symptoms.’
It also is not clear how the teenager in Canada became infected, with the patient having no known exposure to wild birds or farm animals.
In their case, tests show the virus has adapted to be better able to infect humans — with researchers saying the mutations likely happened during the infection.
CDC researchers warn that many other infections may be slipping under the radar
More than 10,000 wild birds and 100million poultry have tested positive for the bird flu virus since the outbreak began in 2022. A total of 500 dairy herds have also been infected.
Yesterday, researchers revealed that bird flu had spread to Hawaii for the first time — after it was detected at a duck sanctuary.
Researchers are concerned that every case of the virus in humans raises the risk that it could gain mutations making it better able to spread between people.
There are fears this has already happened in Cambodia, where three people have died from the virus after catching a new strain that is a hybrid between a type that infects wild birds and a type that infects domestic poultry.
