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 humans.
The unidentified child was suffering from mild respiratory symptoms and had attended a day care center in Alameda County, part of the state’s Bay Area.
They have been isolated at home and are receiving treatment, and none of their family members or playmates have 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 highlights 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 spread to humans.
It is the first reported case in a child in the U.S. and at least the 53rd human case nationwide. Most cases have been linked to exposure to birds or livestock, but in one case an individual had no contact with either.
And in Canada, a teenager who had no contact with cows or birds is in critical condition in hospital after being diagnosed with bird flu.
All of the American 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 undetected and are not being detected or reported.
In a study on blood samples from 115 dairy farm workers in Michigan and Colorado who had tested negative for bird flu or had not been tested at all, the agency found. Seven percent (eight people) had antibodies to the virus.
RED EYE: The H5N1 virus causes eye inflammation, as seen in a Texas dairy farmer who contracted bird flu earlier this year.
While experts are concerned about missed cases, they are encouraged because it means that most people who contract bird flu do not become seriously ill.
However, the CDC warned that each infection increased the risk of the virus acquiring mutations so it could better spread between people and cause serious illness.
In California, health officials said the boy had low levels of the virus in his positive test, suggesting he was not contagious to others.
A second test four days later was negative, suggesting his body had fought off the infection.
It’s unclear how the boy 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, and the sample was sent for confirmatory testing to the CDC to confirm H5N1, the bird flu strain that caused the outbreak in the US.
State health director Dr Tomás Aragón said: “It is natural that people are concerned and we want to reinforce to parents, caregivers and families that, based on the information and data we have, we do not believe the child was contagious “.
And he added: “No human-to-human transmission of avian flu has been documented in any country for more than 15 years.”
The map above shows the locations of bird flu infections in the US during 2024 and during the current outbreak. So far there have been 27 confirmed cases of bird flu in California, and all had previously had mild symptoms.
In the CDC study that looked at 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 of the workers, who were tested between June and August of this year, reported milking the cows or cleaning the milking parlor.
None of the workers who tested positive for bird flu antibodies had worn personal protective equipment (PPE) when working with infected livestock.
Overall, PPE use among study participants was “low,” the researchers said.
The CDC said in the study, published in its Weekly Morbidity and Mortality Reports: ‘This finding supports the need to identify and implement strategies to prevent transmission among dairy cattle to reduce worker exposure.
“And to educate and disseminate dairy workers about prevention, symptoms and where to seek medical care if workers develop symptoms.”
It is also unclear how the teenager became infected in Canada, as the patient had no known exposure to wild birds or farm animals.
In their case, evidence shows that the virus has adapted to better infect humans; The researchers say the mutations likely occurred during infection.
CDC researchers warn that many other infections may be going undetected
More than 10,000 wild birds and 100 million 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 each case of the virus in humans increases the risk that it will acquire mutations that allow it to spread better between people.
This is feared to have 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 birds.