First case of bird flu discovered in children as blood tests show the virus is more widespread than reported

A child in California has tested positive for bird flu, local health officials say — the first pediatric case — amid growing fears that the disease could spread between people.

The unidentified child was suffering from mild respiratory symptoms and had gone to daycare in Alameda County, part of the state’s Bay Area.

They are isolated at home and are receiving treatment. None of their family members or playmates tested positive for the H5N1 virus. Health officials are still investigating how they contracted the virus.

Health officials say the risk to the public remains “low.”

But the case underlines the possibility that 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 U.S. and at least the 53rd human case nationwide. The cases were mostly linked to exposure to birds or livestock, but in one case an individual had no contact with either.

And in Canada, a teenager who has no contact with cows or birds is in critical condition in hospital after being diagnosed with bird flu.

All US patients reported mild symptoms – such as red eyes or mild respiratory symptoms – and none died from the disease.

But CDC researchers said today that many cases have likely gone under the radar and are not being detected or reported.

In a study of blood samples from 115 workers at dairy farms in Michigan and Colorado who tested negative for bird flu or were not tested at all, the agency found seven percent – ​​eight people – had antibodies against the virus.

While experts are concerned about missed cases, they are confident it means most people who contract bird flu will not become seriously ill.

However, the CDC warned that any infection increases the risk that the virus will acquire mutations, making it more likely to spread between people and cause serious illness.

In California, health officials said the child when they tested positive had low levels of the virus, indicating the child was not contagious to others.

A second test taken four days later came back negative, indicating their bodies had fought 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 sent to the CDC for confirmatory testing to confirm H5N1, the bird flu that caused the outbreak in the US.

State health director Dr Tomas Aragon said: ‘It is normal for people to be concerned, and we would like to emphasize to parents, caregivers and families that based on the information and data we have, we do not believe the child was contagious.’

He added: ‘Human-to-human spread of bird flu has not been documented in any country for more than 15 years.’

The above map shows the locations of bird flu infections in the US in 2024 and during the current outbreak. There are now 27 confirmed cases of bird flu in California, all of which previously had mild symptoms

In the CDC study of antibodies in the blood of farmworkers, four of the participants said they remembered being sick around the same time the cows they worked with tested positive for bird flu.

All workers – who were tested between June and August this year – reported having milked the cows or cleaned the parlor.

None of the workers who tested positive for bird flu antibodies had worn personal protective equipment (PPE) when working with infected livestock.

Overall, personal protective equipment use among study participants was “low,” the researchers said.

The CDC said in the study, published in its Weekly reports on morbidity and mortality: ‘This finding supports the need to identify and implement strategies to prevent transmission among dairy cattle to reduce worker exposure.

‘And for education and assistance to dairy workers about prevention, symptoms and where to seek medical attention if the workers develop symptoms.’

It is also not clear how the teenager became infected in Canada, as the patient is not known to have been exposed to wild birds or farm animals.

In their case, tests show the virus has adapted to become better at infecting people – with researchers saying the mutations likely occurred during infection.

CDC researchers warn that many other infections may be flying under the radar

Since the outbreak began in 2022, more than 10,000 wild birds and 100 million poultry have tested positive for the bird flu virus. A total of 500 dairy farms have also been infected.

Yesterday, researchers revealed that bird flu had spread to Hawaii for the first time – after the disease was discovered at a duck sanctuary.

Researchers are concerned that any case of the virus in humans carries the risk that it could acquire mutations that make it more likely to spread between people.

It is feared this has already happened in Cambodia, where three people have died from the virus after contracting a new strain that is a hybrid between a type that infects wild birds and a type that infects domestic poultry.