WASHINGTON, United States (AFP) — An elderly patient in Louisiana is in “critical condition” with severe avian influenza, US authorities announced Wednesday, the first serious human case in the country as fears grow of a possible bird flu pandemic.

The new case brings the total number of infections in the country during the current 2024 outbreak to 61, as California declared an emergency in order to ramp up its response.

Prior patients experienced mild symptoms and recovered at home. But the severity of the Louisiana case has heightened alarm, echoing similar cases worldwide.

Last month, a teenager in Canada was also hospitalized with a severe case of bird flu.

According to the US Centers for Disease Control and Prevention (CDC), the Louisiana patient was exposed to sick and dead birds in backyard flocks.

“The patient is experiencing severe respiratory illness related to H5N1 infection and is currently hospitalized in critical condition,” the Louisiana health department said in a statement to Agence France-Presse, adding the person has underlying medical conditions and is over the age of 65.

“Over the 20-plus years of global experience with this virus, H5 infection has previously been associated with severe illness in other countries, including illnesses that resulted in death in up to 50 percent of cases,” Demetre Daskalakis, a senior CDC official, told reporters on a call.

“The demonstrated potential for this virus to cause severe illness in people continues to highlight the importance of the joint... US federal response,” he added.

Meanwhile, the most populous US state California announced a state of emergency.