The physical space of the MSK Library is permanently closed to visitors as of Friday, May 17, 2024. Please visit this guide for more information.
The physical space of the MSK Library is permanently closed to visitors as of Friday, May 17, 2024. Please visit this guide for more information.
Highly pathogenic avian influenza (HPAI) A(H5) viruses have been detected in U.S. wild aquatic birds, commercial poultry and backyard or hobbyist flocks beginning in January 2022. These are the first detections of HPAI A(H5) viruses in the U.S. since 2016. Preliminary genetic sequencing and RT-PCR testing on some virus specimens shows these viruses are HPAI A(H5N1) viruses from clade 2.3.4.4.
NOTE: On March 29, 2024 the CDC announced new interim recommendations for prevention, monitoring, and public health investigations of highly pathogenic avian influenza A(H5N1) virus in animals. Updates to this page are forthcoming.
| Dairy Cattle: On-going multi-state outbreak | Human Cases: 70 cases in the U.S. |
| Wild Birds: Widespread | Human Deaths: 1 death in the U.S. |
| Poultry Flocks: Sporadic outbreaks | Person-to-person spread: None |
| Mammals: Sporadic infections | Current public health risk: Low |
CDC assessed the risk posed by highly pathogenic avian influenza (HPAI) A(H5N1) viruses to the United States.
The current risk to the general U.S. population is low. The risk to populations exposed to potentially infected animals, including through contaminated surfaces or fluids, is currently assessed as moderate to high. CDC has moderate confidence in this assessment.
Note: The likelihood of exposure is higher among people consuming raw (unpasteurized) milk from infected animals, although the chance of people acquiring H5N1 virus infection from consuming raw milk is not clear at this time.
These data will be updated daily, Monday through Friday, after 4 p.m. to reflect any new data.
Cumulative data on wild birds have been collected since January 20, 2022. Cumulative data on poultry have been collected since February 8, 2022. Cumulative data on humans in the U.S. have been collected since April 28, 2022. Cumulative data on dairy cattle have been collected since March 25, 2024.
February 28 Risk to People in the United States from Highly Pathogen Avian Influenza A(H5N1) Viruses
February 26 CDC A(H5N1) Bird Flu Response Update February 26, 2025
January 15 H5 Bird Flu Response: Focus Areas for Ongoing Public Health Risk Assessment
January 6 Information for Workers Exposed to H5N1 Bird Flu
December 26 Genetic Sequences of Highly Pathogenic Avian Influenza A(H5N1) Viruses Identified in a Person in Louisiana
These technical reports are intended for scientific audiences. Additional information for scientific audiences and the general public is available on CDC’s Information on Bird Flu webpage.
Technical Report: June 2024 Highly Pathogenic Avian Influenza A(H5N1) Viruses
This report provides an update to the April 26, 2024, report to include three additional sporadic human cases (1 in Australia and 2 in the United States) and recent activity in wild birds, poultry, and other animals, including the multi-state outbreak in U.S. dairy cattle, and updated information on monitoring for human infections with highly pathogenic avian influenza A(H5N1) virus infections in the United States.
CDC continues to believe that the overall risk to human health associated with the ongoing outbreaks of highly pathogenic avian influenza A(H5N1) viruses has not changed and remains low to the U.S. general public at this time.