California Child Tests Positive for Bird Flu

WEDNESDAY, Nov. 20, 2024 (HealthDay News) -- A child in California has tested positive for bird flu, despite having no known contact with infected animals, state officials reported Tuesday.

"California has identified a possible bird flu case in a child in Alameda County who was tested for mild upper respiratory symptoms. The child, who has been treated, is recovering at home," the California Department of Public Health (CDPH) said in a news release.

While the patient had no known contact with an infected animal, health officials are investigating a possible exposure to wild birds, the CDPH added.  

Importantly, "the positive test showed a low-level detection of the virus, indicating the child was not likely infectious to others," they noted. "Repeat bird flu testing on the child four days later was negative, and additional testing shows the child was also positive for respiratory viruses that could be the cause of their cold and flu symptoms. The test specimens are being sent to CDC [U.S. Centers for Disease Control and Prevention] for confirmatory testing."

Even as the case was reported, state officials stressed the public health risk remained low.

“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 -- and no human-to-human spread of bird flu has been documented in any country for more than 15 years," said CDPH Director Dr. Tomás Aragón. 

So far this year, 53 people have been confirmed to have bird flu in the United States, according to the CDC; all but one had been exposed to infected poultry or dairy cows.

In the California case, no person-to-person spread of the virus has been detected and the child's family members all tested negative.

Bird flu has been spreading in poultry since 2022, and cases in dairy cows began to crop up in March. The virus was discovered in a pig for the first time last month.

Bird flu infections in people -- nearly all among farmworkers -- have now been confirmed in seven states, with Oregon reporting its first human case last week.

California accounts for the largest share of human bird flu cases in the country, with 27 confirmed infections, not counting the child in Alameda County. Washington has recorded 11 cases, and Colorado 10, CDC data shows.

Earlier this month, Canadian officials announced that a teen in British Columbia had been hospitalized in critical condition with what is believed to be bird flu.

It’s not clear how the teenager picked up the H5N1 virus because the patient is not known to have any contact with infected animals, officials noted. They added that this is the first human case of the virus reported in both the province and Canada.

"The positive test for H5 was performed at the BC Centre for Disease Control’s Public-Health Laboratory," Dr. Bonnie Henry, provincial health officer of British Columbia, said in a statement. "Samples are being sent to the National Microbiology Laboratory in Winnipeg for confirmatory testing."

Testing has been performed on about three dozen people who were in contact with the teen, but none show evidence of infection, Henry added.

Federal health officials also reported recently that a second person in Missouri who wasn't exposed to either poultry or dairy cows had been infected with bird flu.

This person shared a home with a patient who was first hospitalized with bird flu in August, but antibody tests have since shown that symptomatic health care workers who cared for the patient were not infected with the H5N1 virus, the CDC said in a bird flu update.

However, there was some reassuring news: There was no evidence that H5N1 had passed person-to-person because the fact that "these two individuals had identical symptom onset dates support a single common exposure to bird flu rather than person-to-person spread within the household," the CDC noted.

"To date, human-to-human spread of H5 bird flu has not been identified in the United States," the agency added. "CDC believes the immediate risk to the general public from H5N1 bird flu remains low, but people with exposure to infected animals are at higher risk of infection."

The latest cases fuel growing concern among public health experts that the ongoing bird flu outbreak will eventually trigger human-to-human transmission of the virus.

Across the country, more than 549 dairy herds in 15 states have been infected since the outbreak in dairy cows was first confirmed in March. Avian influenza has been spreading in wild and domestic birds in the United States for several years.

“We should be very concerned at this point,” Dr. James Lawler, co-director of the University of Nebraska’s Global Center for Health Security, told the New York Times. “Nobody should be hitting the panic button yet, but we should really be devoting a lot of resources into figuring out what’s going on.”

More information

The CDC has more on bird flu.

SOURCES: California Department of Public Health, news releaase, Nov. 19, 2024; British Columbia Ministry of Health, news release, Nov. 9, 2024; U.S. Centers for Disease Control and Prevention, news releases, Oct. 30, 2024; Oct. 24, 2024, Oct. 18, 2024; Oct. 3, 2024; New York Times