CDC monitoring cases of bird flu across the U.S.

The medical science community is on alert after recent reports of bird flu outbreaks across the U.S.

According to the Centers for Disease Control and Prevention (CDC), there have been more than 90 million poultry impacted by bird flu, also known as H5N1, as well as 46 herds of dairy cows, as of Tuesday.

As for the virus spreading to humans, the second human case was reported in April 2024 in Texas. The CDC said the person was exposed to dairy cows through work. Their only symptom was eye redness, and they were able to recover.

“It’s a Type A flu, so it’s Influenza A, and it manifests the same way as influenza, with high temperatures,” Dr. Francesca Torriani, an infectious disease specialist and the medical director of Infection Prevention and Clinical Epidemiology for UC San Diego Health, told NBC 7.

Torriani explained that the symptoms appear to be mild in the rare human cases reported. According to the CDC, chickens are the most impacted, with outbreaks in nearly every state, including one in San Diego County. Dairy cows have not been nearly as affected. Nine states have reported outbreaks among their cattle, as of Tuesday. However, that’s not what medical experts like Torriani are worried about.

“Dairy cows [are] less of a concern, but as some other people in the scientific community have pointed out, where we are concerned is if this could be translated to pigs,” Torriani said.

Pigs, Torriani continued, have a variety of influenza strains that could make bird flu more easily transmitted to humans. Still, based on the research currently available, she clarified there should not be cause for concern.

“It is not so much that there’s bird flu now, but it’s really being on top of it and doing the adequate surveillance so that people can put prevention measures in place,” Torriani said.

One of those surveillance measures includes looking at wastewater testing throughout the state. As of the latest report, shared with NBC 7 by a spokesperson for the San Diego County Health and Human Services Agency, some areas in California, including Indio and Riverside, have seen upward trends in Influenza A. This would include, but is not limited to, bird flu. However, the spokesperson added, San Diego has only seen a slight uptick and numbers are still much lower than they were during flu season. 

Torriani shared that more testing and surveillance is expected on a national level to keep an eye on H5N1.

The CDC has tips on its website to protect yourself from bird flu, including avoiding dead birds, if you come across them.