A patient in Louisiana has been hospitalized due to a severe infection of the avian influenza A(H5N1) virus, commonly referred to as H5N1 bird flu. Confirmed by the Centers for Disease Control and Prevention (CDC) on December 13, this case represents the first serious illness caused by this virus in the United States. Since April 2024, there have been 61 reported human H5 bird flu cases nationwide.
Genomic analysis of the virus revealed that the strain belongs to the D1.1 genotype, which corresponds to other recently identified D1.1 strains found in wild birds and poultry within the United States, as well as in human cases reported in British Columbia, Canada, and Washington state. This variant differs from the B3.13 genotype observed in dairy cows and sporadic human infections across various states. The CDC is currently undertaking further genomic sequencing and isolating the virus from clinical samples connected to this Louisiana patient.
Investigators have traced the infection’s origin to the patient’s exposure to sick and deceased birds in backyard flocks, marking the first instance in the U.S. where H5N1 bird flu has been associated with such exposure. Although rare, the occurrence of severe H5N1 infection in humans is not unprecedented, as there have been similar cases globally in previous years, some resulting in fatality. Importantly, there has been no evidence of human-to-human transmission of the virus.
This case highlights the need for awareness regarding exposure to not only commercial poultry but also wild birds and backyard flocks. Individuals engaged in activities that may lead to contact with infected animals, such as backyard flock owners and bird enthusiasts, are encouraged to adhere to CDC safety recommendations to minimize risk.
To prevent H5 bird flu transmission, it is advisable to limit exposure to infected birds. Infected organisms often expel the virus through saliva, feces, and respiratory secretions. Consequently, individuals should avoid contact with sick or deceased wildlife and poultry whenever possible.
For those who must work closely with potentially infected animals, using appropriate personal protective equipment (PPE) is essential. It’s crucial to remember that even healthy-looking wild birds can carry the avian influenza virus.
As cases continue to be monitored, the CDC maintains that the immediate risk of H5N1 bird flu to public health remains low. For updated information on H5 bird flu in the United States, including case counts and CDC’s ongoing response, individuals can visit the CDC’s current situation page regarding H5 bird flu.
This situation serves as a reminder of the importance of wildlife health monitoring and public health preparedness. Continued vigilance and adherence to safety guidelines can ensure both the health of humans and the well-being of animal populations.