The United States reported its first severe human case of bird flu on Wednesday, involving a Louisiana resident, as California declared a state of emergency to address the escalating outbreak.

The Louisiana patient was hospitalized in critical condition after suspected contact with an infected backyard flock, according to the U.S. Centers for Disease Control and Prevention (CDC). The case, confirmed on Dec. 13, is the first in the country linked to severe illness from the avian flu.

“This is the first case of H5N1 bird flu in the U.S. that has been linked to exposure to a backyard flock,” the CDC said in a statement.

As the CDC confirmed the bird flu case, California Gov. Gavin Newsom declared a state of emergency on Wednesday, describing it as a precautionary measure to help contain the virus’s spread.

To date, no person-to-person spread of the virus has been detected in California and nearly all infected individuals had exposure to infected cattle, the statement read.

“This proclamation is a targeted action to ensure government agencies have the resources and flexibility they need to respond quickly to this outbreak. Building on California’s testing and monitoring system — the largest in the nation — we are committed to further protecting public health, supporting our agriculture industry, and ensuring that Californians have access to accurate, up-to-date information. While the risk to the public remains low, we will continue to take all necessary steps to prevent the spread of this virus,” Newsom said in a statement.

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Since April, there have been a total of 61 reported human cases of H5N1 bird flu reported in the U.S. The virus has spread in 16 states among dairy cattle, following its first confirmed detection in Texas and Kansas in March.

The recent bird flu case in Louisiana highlights the ongoing spread of the H5N1 avian influenza virus, with genome data showing the virus belongs to the D1.1 genotype, the CDC said. This genotype has been linked to recent detections in wild birds and poultry across the U.S., as well as human cases in British Columbia.

On Nov. 3, the Public Health Agency of Canada confirmed that a teenager had contracted a human case of bird flu, caused by the influenza A (H5N1) virus. It marked the first domestically acquired human case of bird flu in Canada. As of Nov. 25, the province reported that the teen remains in critical condition.

Despite this latest case in Louisiana, the CDC maintains that the overall risk to public health from H5N1 remains low. In Canada, the risk also remains low.

While there have been several outbreaks of bird flu on dairy farms in multiple states, the virus has not been detected on dairy farms anywhere in Canada.

Human-to-human transmission of H5N1 — a strain of highly pathogenic avian influenza — is rare with no evidence of sustained transmission, experts say. The majority of human cases in the U.S. and around the world have been due to contact with infected birds, farm animals or wildlife.

— With files from the Canadian Press and Reuters