H5 Bird Flu: Current Situation

What to know

  • H5 bird flu is widespread in wild birds worldwide and is causing outbreaks in poultry and U.S. dairy cows with several recent human cases in U.S. dairy and poultry workers.
  • While the current public health risk is low, CDC is watching the situation carefully and working with states to monitor people with animal exposures.
  • CDC is using its flu surveillance systems to monitor for H5 bird flu activity in people.
H5N1 Bird Flu How is it Spreading?

Current situation

H5 Bird Flu Detections in USA

• Dairy cattle: Ongoing multi-state outbreak

• Wild Birds: Widespread

• Poultry Flocks: Sporadic outbreaks

• Mammals: Sporadic infections

• Person-to-person spread: None

• Current public health risk: Low

Confirmed human case summary during the 2024 outbreak, by state and exposure source


Exposure Source

Exposure Source
State Exposure Associated with Commercial Agriculture and Related Operations Other Animal Exposure Exposure Source Unknown State Total
Dairy Herds (Cattle) Poultry Farms
and Culling Operations
California 35 0 0 1 36
Colorado 1 9 0 0 10
Louisiana 0 0 1 0 1
Michigan 2 0 0 0 2
Missouri 0 0 0 1 1
Oregon 0 1 0 0 1
Texas 1 0 0 0 1
Washington 0 11 0 0 11
Wisconsin 0 1 0 0 1
Source Total 39 22 1 2 64

NOTE: One additional case was previously detected in a poultry worker in Colorado in 2022.

Exposure was related to other animals such as backyard flocks, wild birds, or other mammals
Exposure source was not able to be identified

Probable human case summary during the 2024 outbreak, by state and exposure source

When a case tests positive for H5 at a public health laboratory but testing at CDC is not able to confirm H5 infection, per Council of State and Territorial Epidemiologists (CSTE) guidance, a case is reported as probable.

  • Probable cases with commercial poultry exposure (e.g., poultry farms or culling operations):
    • Washington (3)
    • Arizona (2)
  • Probable cases with commercial dairy (cattle) exposure:
    • California (1)
  • Probable cases with exposure source unknown:
    • Delaware (1)

Confirmed and probable cases are typically updated by 5 PM EST on Mondays (for cases confirmed by CDC on Friday, Saturday, or Sunday), Wednesdays (for cases confirmed by CDC on Monday or Tuesday), and Fridays (for cases confirmed by CDC on Wednesday and Thursday). Affected states may report cases more frequently.

H5 Monitoring in People

CDC influenza (flu) surveillance systems show no indicators of unusual influenza activity in people, including avian influenza A(H5).

National flu surveillance (since February 25, 2024)

Targeted H5 surveillance (since March 24, 2024)

Detections in Animals

  • 10,852 wild birds detected as of 12/17/2024 | Full Report
  • 51 jurisdictions with bird flu in wild birds
  • 125,099,796 poultry affected as of 12/20/2024 | Full Report
  • 50 states with outbreaks in poultry
  • 875 dairy herds affected as of 12/20/2024 | Full Report
  • 16 states with outbreaks in dairy cows

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.

What CDC is doing

Protective Actions for People