Sat Dec 28 07:10:00 UTC 2024: ## CDC Reports Genetic Changes in HPAI A(H5N1) Virus from Severe Louisiana Case, Risk to Public Remains Low
**Atlanta, GA (December 26, 2024)** – The Centers for Disease Control and Prevention (CDC) today announced the sequencing of highly pathogenic avian influenza (HPAI) A(H5N1) viruses from a Louisiana patient who experienced severe illness. Analysis revealed low-frequency mutations in the hemagglutinin (HA) gene of one respiratory specimen, suggesting these changes emerged after the patient was infected, rather than being present in the initial avian source.
The patient was infected with the D1.1 genotype of the virus, closely related to strains recently found in wild birds and poultry in the U.S. and Canada. While the HA gene mutations were rare and have been observed in previous severe human cases, they were not found in poultry samples from the patient’s property. This suggests the mutations developed during the patient’s illness. Importantly, no human-to-human transmission has been identified.
The CDC conducted deep sequencing of two respiratory specimens, comparing the genetic material to sequences from dairy cows, wild birds, poultry, and previous human cases. No changes associated with antiviral drug resistance were detected in other viral gene segments.
The complete genome sequences are publicly available on GISAID and GenBank. Although the mutations are concerning, they are considered low-frequency and were likely generated during the replication of the virus in the patient’s body. The overall risk to the general public remains low, according to the CDC.
The CDC emphasizes the importance of continued genomic surveillance in both humans and animals, controlling avian influenza outbreaks in poultry and cattle, and implementing preventative measures for individuals exposed to infected animals or environments.
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