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 | Humans: 9 cases in the U.S. |
| Wild Birds: Widespread | Person-to-person spread: None |
| Poultry Flocks: Sporadic outbreaks | Current public health risk: Low |
| Mammals: Sporadic infections |
July 14, 2024 -- CDC Confirms Human Cases of H5 Bird Flu Among Colorado Poultry Workers
July 12, 2024 -- Colorado Reports Three Presumptive Positive H5 Cases in Poultry Workers
July 11, 2024 -- CDC Issues Updated Guidance to Help Prevent Spread of Flu at Agricultural Fairs
July 3, 2024 -- CDC Reports Fourth Human Case of H5 Bird Flu Tied to Dairy Cow Outbreak
June 14, 2024 -- Study Shows Ferrets Became Sick with A(H5N1) Virus After Eye Exposure
The CDC provides updates on its response activities related to the multistate outbreak of avian influenza A(H5N1) virus, or "H5N1 bird flu," in dairy cows and other animals in the United States.
CDC continues to respond to the public health challenge posed by a multistate outbreak of avian influenza A(H5N1) virus, or “H5N1 bird flu,” in dairy cows and other animals in the United States. CDC is working in collaboration with the U.S. Department of Agriculture (USDA), the Food and Drug Administration (FDA), state public health and animal health officials, and other partners using a One Health approach.
Four human cases of A(H5) infection associated with this outbreak in U.S. dairy cows have been reported. Based on the information available at this time, CDC’s current H5N1 bird flu human health risk assessment for the U.S. general public remains low.
On the animal health side, USDA is reporting that 151 dairy cow herds in 12 U.S. states have confirmed cases of avian influenza A(H5N1) virus infections in dairy cows as the number of infected herds continues to grow.
Among other activities previously reported in past spotlights and still ongoing, recent highlights of CDC's response to this include updates on the recent human case in Colorado:
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.