First Case of Severe H5N1 Bird Flu in US: Louisiana Resident Hospitalized
The Louisiana Department of Health has confirmed that a resident of the state is hospitalized in critical condition with severe respiratory illness caused by the H5N1 bird flu virus. This marks the first instance of severe illness linked to the virus in the United States, according to the Centers for Disease Control and Prevention (CDC). The patient, who is over 65 years old and has underlying health conditions, was reported to have contact with sick and dead wild and backyard birds thought to be infected with the virus.
Patient’s Condition and Investigation
The Louisiana Department of Health had initially reported a presumptive positive case of H5N1 on Friday, but declined to provide further details due to patient confidentiality and an ongoing public health investigation. However, in a follow-up statement, Emma Herrock, a spokesperson for the department, revealed that the patient is experiencing severe respiratory symptoms and is being treated at a local hospital.
Genetic Data and Strain Identification
The CDC collected partial genetic data of the H5N1 strain infecting the patient, which was found to be of the D1.1 genotype. This genotype has been detected in wild birds and some poultry in the US, and is also the same type seen in a Canadian teenager who was hospitalized in critical condition from the virus last month. Notably, it is distinct from the B3.13 genotype circulating in US dairy cows.
Global Context and Risk Assessment
The CDC emphasized that while this case is severe, it does not change their overall assessment of the immediate risk to public health from H5N1 bird flu, which remains low. According to the World Health Organization (WHO), there have been 939 human cases of H5N1 detected globally between January 2003 and November 2024, with a case fatality rate of 49%. In the US, there have been 61 reported human cases of H5N1 this year, almost all of which were mild infections.
Significance of Louisiana Case
The case in Louisiana is significant because it marks the first severe H5N1 case linked to an animal exposure that was not in a commercial operation. The patient’s contact with sick and dead wild and backyard birds suggests that the virus can be transmitted through direct contact with infected animals, which is a concern for public health officials.
CDC Statement
The CDC statement notes that "a sporadic case of severe H5N1 bird flu illness in a person is not unexpected… Avian influenza A(H5N1) virus infection has previously been associated with severe human illness in other countries during 2024 and prior years, including illness resulting in death. No person-to-person spread of H5 bird flu has been detected."
Public Health Implications
The Louisiana Department of Health is working closely with the CDC to investigate the source of the outbreak and prevent further transmission. The incident highlights the importance of public health measures, such as proper hygiene practices, vaccination, and disease surveillance, in preventing the spread of infectious diseases.
Conclusion
The case of H5N1 bird flu in Louisiana serves as a reminder of the ongoing threat posed by this virus to human health. While the risk is considered low, it is essential for public health officials to remain vigilant and take proactive measures to prevent further transmission.