Federal health officials have confirmed the first severe case of bird flu in the United States, marking a concerning milestone in an outbreak that has devastated poultry farms and impacted dairy herds nationwide. The Centers for Disease Control and Prevention (CDC) reported on Wednesday that a patient in Louisiana was hospitalized after contracting the H5N1 strain of bird flu.
The strain linked to the Louisiana case has been previously detected in wild birds and poultry and differs from the variant infecting dairy cattle. State officials disclosed the hospitalization last Friday but provided limited details on the patient’s condition.
This Louisiana case is the most severe among the 61 confirmed human H5N1 infections in the U.S. since April. Most previous cases have been mild. In August, a person in Missouri was hospitalized after testing positive for H5N1, but the CDC later clarified that the hospitalization was not directly caused by the virus. Meanwhile, Canada reported a severe H5N1 case in November when a teenager in British Columbia required hospitalization.
Despite the severity of the Louisiana case, the CDC maintains there is no evidence of human-to-human transmission and continues to assert that the risk to the general public remains low.
“Individuals who work with or have recreational contact with infected animals face a higher risk of infection,” said Dr. Demetre Daskalakis, director of the CDC’s National Center for Immunization and Respiratory Diseases. “It’s critical that they adhere to CDC’s recommended precautions when dealing with infected or potentially infected animals.”
The Louisiana patient reportedly contracted the virus after exposure to sick and deceased birds from a backyard poultry flock. This marks the first human case tied to a backyard flock, contrasting with the 37 cases linked to commercial cattle and 21 associated with commercial poultry farms. Two cases this year involved individuals with no known animal exposure.
Bird Flu‘s Escalating Impact
The H5N1 strain, long feared for its potential to trigger a global pandemic, continues its relentless spread across the U.S. The Department of Agriculture (USDA) has identified outbreaks in 865 dairy herds this year, with 315 confirmed in the past month alone. California, where bird flu has struck 645 dairies, declared a state of emergency on Wednesday.
Globally, H5N1 has caused severe illness and fatalities. In some countries, up to 50% of reported cases have resulted in death, according to Daskalakis. While the Louisiana case underscores the virus’s potential danger, experts caution that the current U.S. risk remains manageable with proper precautions.
Response Under Scrutiny
The federal and state responses to the outbreak have faced criticism for perceived delays. The USDA only recently initiated a national program to test unprocessed milk for the virus—a step experts had called for months earlier.
Eric Deeble, USDA’s deputy undersecretary for marketing and regulatory programs, defended the agency’s timeline. “We took this step because of changing circumstances on the ground,” Deeble said during a press call Wednesday. “This strategy was not delayed for political reasons.”
Currently, 13 states are participating in the milk testing program, with more expected to join in the coming weeks. Additionally, the USDA has greenlit seven safety trials for H5N1 vaccine candidates for cattle, one of which is already underway. However, Deeble cautioned that bovine vaccines remain in early development and are not an immediate solution.
Progress on Vaccination
In a separate development, CDC scientists published promising results from a study on an mRNA-based bird flu vaccine. Tested on ferrets—a standard model for studying influenza—vaccinated animals survived H5N1 exposure, while unvaccinated ones did not.
“This trial supports the critical role of vaccination in preventing severe disease,” Daskalakis noted, adding that the research offers hope for mitigating the virus’s impact on both humans and animals.
As the outbreak evolves, experts emphasize vigilance, targeted responses, and adherence to preventive measures as key to controlling the spread and minimizing public health risks.