The United States Centers for Disease Control and Prevention (CDC) confirmed that the first severe human case of H5N1 bird flu in Louisiana was reported on December 18, 2024. The Louisiana resident was hospitalized in life-threatening condition after contact with an infected backyard flock. Dr. Demetre Daskalakis, director of the CDC National Center for Immunization and Respiratory Diseases stated that this first severe U.S. case tied to non-commercial poultry settings.
A 65-year-old patient with severe respiratory illness underscores the emerging health risks posed by H5N1 virus. Most of the U.S. cases are mainly due to dairy cattle. Since the outbreak began in April. This case contains the D1.1 genotype generally observed in wild birds and poultry. This strain is different from the B3.13 genotype which is mainly observed in dairy cattle, farm workers, and poultry in multiple states.
California, which is a major milk producer, announced a state of emergency as the H5N1 virus spread notably among dairy herds. It mainly infected more farm workers this year. Since March, a total of 860 dairy herds have been infected in 16 states. Since 2022, there deaths of 123 million poultry have been reported. Since late August, 60% of 649 people tested positive for bird flu. Hence Governor Gavin Newsom declared a medical emergency in California. This measure is proposed to rationalize the state’s response by allowing extreme flexibility in staffing, contracting, and other rules and regulations. Newsom’s statement resulted in the virus’s expansion from the Central Valley to southern California dairies, involving a move from regional containment to statewide exploring.
Nationwide the CDC reported 61 human cases of H5N1 virus this year. Most of the cases are infected due to dairy poultry and cows. Health officials announced that this virus increases the risk to individuals such as animal workers, workers in backyard flocks, and animal hunters. Infected animals can spread this virus through saliva, mucus, feces, and other bodily fluids. This virus also infects individuals who are drinking unpasteurized milk. Two pediatric cases were reported in November. One teenager case was hospitalized in serious condition in British Columbia. Furthermore, the Los Angeles Department of Public Health has currently confirmed two H5N1 cases in indoor cats that consumed raw or unpasteurized milk. Thus, the U.S. Department of Agriculture has implemented nationwide H5NI testing for unpasteurized milk. This bird flu testing plan is implemented to cover half of the milk supply across 13 U.S.
Dr. Amesh Adalja, Johns Hopkins Center for Health Security, says “The nature of the virus transmission from cattle or birds plays an important role in the severity of human infection.” Finally, the CDC has reported that the overall risk of the bird flu virus to the public remains minimal. On the contrary, this Louisiana case highlights the importance of precautions for people who work closely with animals, especially in non-commercial poultry settings. CDC recommended that U.S. population eat completely cooked poultry, eggs, and beef, avoid contact with sick or dead animals, and refrain from consuming raw or unpasteurized milk products or food. Health executives also emphasize the significance of genomic surveillance in monitoring the evolution of viruses.
The ongoing outbreak has led to improved efforts to update bird flu vaccines to improve the risks of a potential pandemic. Health experts identify that many questions about the virus’s spread into humans remain unanswered, including the specific factors that enhance individual risk. Dr. Rebecca Christofferson, a virologist, from Louisiana State University states “Knowing these spillovers is significant for avoiding future outbreaks.”
References:
- Centers for Disease Control and Prevention (CDC). CDC Confirms First Severe Case of H5N1 Bird Flu in the United States. 2024. https://www.cdc.gov/media/releases/2024/m1218-h5n1-flu.html
- Karen Weintraub and Eduardo Cuevas. Louisiana bird flu patient is first in US to have a ‘severe’ case. USA Today. December 18, 2024. Accessed from https://www.usatoday.com/story/news/health/2024/12/18/louisiana-bird-flu-patient-severe-symptoms/77074515007/
