At a glance
Overview
A(H5) Bird Flu Surveillance in U.S.
On July 7, 2025, CDC streamlined A(H5) bird flu updates with routine influenza data updates and updated reporting cadences to reflect the current public health situation. As such, several changes were made to this page:
- Data on the number of people monitored and tested for bird flu, as well as animal and epidemiologically linked human cases are reported monthly.
- Data that are reported in CDC's FluView, National Wastewater Surveillance System (NWSS), and The National Syndromic Surveillance Program (NSSP) will not be updated here but can be found on those respective webpages.
CDC uses multiple systems to monitor national, state, and local level influenza data during the current avian influenza A(H5) situation.
- Influenza virus and illness activity are monitored year-round through a collaborative effort between CDC and many partners, including state, local, and territorial health departments; public health and clinical laboratories; clinics; and emergency departments.
- Human cases of novel influenza, which are human infections with non-human influenza A viruses that are different from currently spreading seasonal human influenza viruses, are nationally notifiable. Every identified case is investigated and reported to CDC.
- CDC is actively looking at multiple flu indicators during the current situation to monitor for influenza A(H5) viruses, including looking for spread of the virus to, or among people, in jurisdictions where the virus has been identified in people or animals. More information is available: FluView.
Monitoring of Persons Exposed to Infected Animals*
Note: Monitoring data of persons exposed to infected animals will be updated on the first Friday of every month.
February 2022 – Present
CDC and state and local health departments monitor people exposed to infected birds, poultry, dairy cows or other animals for 10 days after exposure. Between February 2022 and January 31, 2026, there have been
- At least 31,900 people monitored and
- At least 1,300 people tested for novel influenza A
Current HPAI Outbreak (MMWR Week 40 2025 – Present)
CDC and state and local health departments monitor people exposed to infected birds, poultry, dairy cows and other animals for 10 days after exposure. Between September 28, 2025 and January 31, 2026 there have been
- At least 2,750 people monitored
- At least 120 persons tested for novel influenza A
*CDC numbers are based on weekly state aggregate reports since 2022. CDC defers to states for updated information on people being monitored and tested.
Monitoring for Novel Influenza A virus infections among people, including Influenza A(H5)
Note: Animal and epidemiologically linked human cases will be updated on the first Friday of every month. Data presented through: 1/31/2026; Data as of: 2/4/2026
Influenza A(H5) virus infections in humans exposed to affected animals by state
Data presented through: 1/31/2026; Data as of: 2/4/2026
Influenza A(H5) affected dairy herds and epidemiologically linked human cases
Data presented through: 1/31/2026; Data as of: 2/4/2026
Influenza A(H5) affected commercial poultry flocks and epidemiologically linked human cases
Influenza A(H5) affected backyard flocks and epidemiologically linked human cases
Data presented through: 1/31/2026; Data as of: 2/4/2026
Influenza Surveillance Systems
CDC has multiple surveillance systems that are used year-round to monitor key flu indicators. These data are reviewed comprehensively each week.
Case Reporting
For the latest case counts, please visit the A(H5) Bird Flu: Current Situation page.
Public Health Laboratory Monitoring
For more information on Public Health Laboratory testing visit FluView
Clinical Laboratory Trends
For more information on Clinical Laboratory trends visit FluView
Emergency Departments
For data on emergency department visits visit data.cdc.gov
Wastewater Surveillance
For more information on wastewater surveillance visit CDC’s National Wastewater Surveillance System (NWSS)