By Ilena Peng and Gerry Smith

A Louisiana resident has been hospitalized with bird flu, marking the first severe human case of avian influenza in the U.S., while California declared a state of emergency to respond to the growing outbreak among dairy cows.

The Louisiana patient had exposure to sick and dead birds in backyard flocks, and an investigation into the source of the infection is still ongoing, the Centers for Disease Control and Prevention said on Wednesday. There’s no evidence the virus known as H5N1 is spreading from person-to-person, and the risk to humans remains low, the agency said.

There have been 61 human cases of bird flu detected in the U.S. since April, with most patients reporting mild symptoms. Sporadic cases of severe illness aren’t unexpected and have occurred in other countries, the CDC said.

Also on Wednesday, California Governor Gavin Newsom declared an emergency to help contain an outbreak that’s been spreading among dairy cows. The move gives state and local agencies more flexibility around staffing, contracting, and other rules to support the response. More than half of the U.S. bird flu infections in humans have occurred in California, where nearly 650 herds have been affected.

“This proclamation is a targeted action to ensure government agencies have the resources and flexibility they need to respond quickly to this outbreak,” Newsom said in a statement. 

Louisiana patient

The virus infecting the Louisiana patient belongs to a strain related to those that were recently detected in wild birds and people in Washington and British Columbia, according to the CDC. It is separate from the variant spreading among dairy cows in the US.

The Louisiana Department of Health initially reported the infection last Friday, noting that the presumed case was the first in the state.

The individual was hospitalized in relation to the influenza diagnosis. Further testing revealed the H5 subtype, Demetre Daskalakis, the CDC’s Director of the National Center for Immunization and Respiratory Diseases, said on a call with journalists.

“The large number of animals, birds and mammals, infected with H5 bird flu increases the risk of virus potentially infecting people and potentially adapting to cause human-to-human spread,” Daskalakis said, noting the current risk is low. The agency is working to “stay ahead of the curve” should vaccines be needed for people, he said.

The CDC declined to provide more details on the patient or their status during a media briefing, deferring to the Louisiana Department of Health.

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