A possible case of H5N1 bird flu virus in a California child has been linked to raw milk consumption and is under investigation by state health officials and the CDC.
The patient experienced fever and vomiting after drinking raw milk and has since recovered, according to an announcement by Marin County Public Health. Officials said that the risk to the public remains low, as there was no evidence of person-to person transmission between the child and her family members.
The case stands out for being outside the usual farm work setting.
Since March, at least 58 people in the U.S. have been reportedly infected with bird flu, mostly poultry and dairy farm workers who became mildly ill after close contact with infected animals. California alone accounts for 32 confirmed cases of bird flu this year.
"Bird flu infections in humans are uncommon but there are ongoing outbreaks in dairy cattle and poultry farms in the United States," said Lisa Santora, MD, MPH, Marin County's public health officer, in a statement. "The risk to the public remains low, as bird flu spread from person to person is rare."
Nevertheless, there is concern that if more people are exposed to the virus, it could mutate to spread more easily in humans.
More than 700 herds have been confirmed to be infected with bird flu in 15 states. Raw milk from infected cows has been shown to contain very high levels of the H5N1 virus.
To limit the spread of H5N1, federal officials ordered testing of raw milk for bird flu last week. Testing will begin in six states -- California, Colorado, Michigan, Mississippi, Oregon, and Pennsylvania -- starting on December 16.
In California, officials recently quarantined Raw Farm in Fresno and halted distribution of its milk after bird flu virus was detected in samples.
Without pasteurization, raw milk is considered risky because it may contain dangerous bacteria and viruses. Campylobacter and Salmonella are the usual suspects in outbreaks linked to unpasteurized milk. Children and teenagers have been disproportionately affected by these outbreaks.
Despite years of warnings, sales of raw cow's milk are still trending upward. FDA data from 2016 and 2019 showed that 4.4% of Americans drank raw milk at least once a year, and 1% drank it once a week or more.
Regulations around raw milk vary widely across states, with some allowing retail sales in stores and others limiting sales to farms. In California, retail sale of raw milk is legal, but licensed sellers must label it as such with a warning.
Healthcare providers are advised to consider H5N1 virus in persons with fever, gastrointestinal symptoms, respiratory symptoms, and/or conjunctivitis with recent consumption of raw milk products or exposure to animals suspected or confirmed to have avian influenza.
There may be more bird flu cases going undetected, as some experts believe that H5N1 infections could be easily missed in people.