Bird flu detected in milk from Maricopa County cows for the 1st time

H5N1 bird flu has been detected in milk from Arizona cattle for the first time.

In a press release, the Arizona Department of Agriculture said milk from every dairy in Arizona has been tested for bird flu at least once since January, but this week was the first time a test turned up positive.

The Maricopa County dairy herd that tested positive is now under quarantine, though the cattle are so far showing no symptoms of the virus, the press release said.

The agriculture department said pasteurized milk is safe to consume and risk to the general public remains very low. But the state and county health departments are monitoring workers from the affected farm.

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'It’s exploding faster and faster': Arizona farms, consumers face the growing toll of bird flu

Phil Latzman

Bird flu is forcing farmers in Arizona and beyond to euthanize millions of laying hens and driving up egg prices. Experts say producers may have to starting using a vaccine on birds, and some worry the virus could mutate to affect humans.

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The Centers for Disease Control and Prevention has confirmed 68 human cases of the virus nationwide since 2024, the majority of which involved close contact with sick animals.

The CDC has has been tracking an outbreak of avian flu across the U.S. since 2022. The first infections among a commercial poultry flock in Arizona were reported on a Pinal County farm in mid–November. The state health department identified two likely human cases of the virus among workers from that farm. Animals on other poultry farms have become infected in the time since.