An Alameda County child with mild upper respiratory symptoms has tested positive for bird flu, state public health officials announced Tuesday. The potential infection is the first known case in California that does not appear to have come from contact with infected cattle.

State health officials are waiting for the Centers for Disease Control and Prevention to confirm the test result.

Public health investigators suspect the infection may have come from wild birds, which are the primary carriers of bird flu, according to a statement from the California Department of Public Health. The agency did not release information describing the child’s interactions with wildlife.

The child had mild respiratory symptoms and tested positive for multiple viruses, according to Austin Wingate, a spokesman for the Alameda County Health Department.

Doctors did not initially suspect bird flu. Officials detected it through routine flu subtyping, Wingate said. Family members tested negative for bird flu but also had other viruses.

Officials are working to notify and test the child’s close contacts, which include people from a daycare the child attended.

“We want to reinforce to parents, carers and families that, based on the information and data we have, we do not believe the child was infectious – and no human-to-human spread of bird flu has been documented in any country for more than . for over 15 years”, said the state public health officer, dr. Tomás Aragón, in a statement.

Aragón stressed that the risk to the general public remains low. People can become infected through close contact with infected animalsAccording to the CDC. Dairy and poultry workers and people who work with wildlife face the highest risk of contracting the virus.

Some infectious disease experts are concerned about what this case might signal wider outbreak of bird flu that has swept the countrywhich started in 2022.

“We see the numbers going up, the number of infected farms, the number of farm workers, now we have this baby. All of these signs to me suggest that things are going in the wrong direction, not the right direction,” said Sam Scarpino, an epidemiologist at Northeastern University in Boston who is not involved in the California disease investigation.

Cases are spreading in factories in the Central Valley

The case comes as California is dealing with the nation’s largest bird flu outbreak among cattle and farm workers. I am 26 confirmed cases of bird flu in humans primarily in the Central Valley, where the virus passed 335 herdsaccording to state health and agriculture officials. Dairy workers contracted the virus through close contact with infected cows.

The state health department has distributed more than 3 million personal protective equipment to farm workers. It also secured 5,000 doses of seasonal flu vaccine for CDC farm workers.

The federal government has a small stockpile of bird flu vaccines, but they have not been distributed. Instead, health officials are encouraging people to get vaccinated against flu, COVID-19 and respiratory syncytial virus to help prevent co-infections like the child had.

“We want to make sure, in general, that we’re promoting people to get up to date on vaccines and protect themselves from seasonal illnesses, seasonal flu,” said Dr. Erica Pan, the state’s top epidemiologist, in a previous interview with CalMatters.

Scarpino said California has done a good job testing farm workers compared to other states where sick cattle have infected people, contributing to the relatively high number of confirmed cases, but global surveillance efforts need to be stepped up.

As seasonal flu rates rise, it will become harder for public health labs to detect rare viruses such as H5N1 bird flu, Scarpino said.

Bird flu is present in California sewage

The bird flu virus has appeared in 17 California sewer systems, according to the Centers for Disease Control and Prevention. The positive detections are occurring mainly in Northern California, including Alameda, San Francisco, Sonoma, Contra Costa and Sacramento. Wastewater surveillance cannot determine the source of the virus, but infections among wild waterfowl may contribute to its presence.

Maurice Pitesky, a researcher at UC Davis who studies bird flu in waterfowl, said it is rare for the virus to pass from birds to humans, but it has happened. The virus is endemic among wild birds, Pitesky said, and has also been detected other California mammalsincluding bobcats, skunks and mountain lions.

“As the virus continues to evolve in a mammalian host — whether it’s dairy cows, whether it’s cats, or whatever species it’s affected — it will continue to adapt,” said Pitesky. “As it adapts more and more, it has more potential to cause even more problems.”

Berkeleyside is a media partner of CalMattersa nonpartisan, nonprofit news site covering the State Capitol and public policy issues in California. Berkeleyside occasionally republishes CalMatters stories that we think will be of interest to our readers.

This story was supported by the California Health Care Foundation (CHCF), which works to ensure people have access to the care they need, when they need it, at a price they can afford. Visit www.chcf.org to learn more.