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Avian Influenza

Current U.S. Bird Flu Situation in Humans

H5N1 Bird Flu: Current Situation
Last Updated: July 16, 2024
 
H5 Human Cases

Total Reported Human Cases in the United States: 9 (since 2022)

  • 4 following exposure to dairy cows (reported between 4/1/2024 and 7/3/2024 | Full Report
  • 5 following exposure to poultry (reported between 4/28/2022 and 7/14/2024) | Full Report
  • States with Reported Case(s): 3

*5 of the 9 H5 human cases reported in the US have been confirmed as H5N1.

CDC Monitoring Avian Influenza in Humans
Weekly Snapshot for week ending July 6, 2024
 
Overview

This page provides information on how CDC systems that monitor national, state, and local level influenza data are being used during the current avian influenza A(H5N1) 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(H5N1) viruses, including looking for spread of the virus to, or among people, in jurisdictions where the virus has been identified in people or animals.
Monitoring of Persons Exposed to Infected Animals
Poultry/Birds: February 2022 - Present

CDC and state and local health departments monitor people exposed to infected birds, poultry or other animals for 10 days after exposure. Between February 2022 and now, there have been

  • At least 10,600 people monitored
  • At least 375 people tested for novel influenza A
 
Dairy Cattle: March 2024 - Present

CDC and state and local health departments monitor people exposed to infected cattle for 10 days after exposure.  Between March 2024 and now, there have been

Main Findings from Surveillance Systems

CDC has multiple surveillance systems that are used year-round to monitor key flu indicators. These data are reviewed comprehensively each week. Taken together, as of June 14, 2024, these systems currently show no indicators of unusual flu activity in people, including avian influenza A(H5N1) viruses.

Case Reporting

In 2024, four human cases of influenza A(H5) virus infection have been reported by three states (Texas, Michigan, Colorado), following exposure to dairy cattle. A total of 5 human cases of A(H5) have been reported in the United States ever, with the first case occurring in 2022, following exposure to presumably infected poultry.
Public Health Laboratory Monitoring

No novel influenza A positive test results, including for influenza A(H5) virus, were reported by public health laboratories for the week ending July 6, 2024. Since February 25, 2024, 34,091 specimens have been tested using a protocol that would have detected A(H5) and other novel viruses.
Clinical Laboratory Trends CDC has not identified any unusual trends in reported clinical laboratory data at the national, state, or local levels.
Emergency Departments CDC has not identified any unusual trends in emergency department visits associated with influenza or potentially related symptoms at the national, state, or local levels.
Wastewater Surveillance During the two most recent weeks, (June 23, 2024–July 6, 2024), a total of 340 of 770 sites reported data meeting criteria for analysis for influenza A virus for both weeks or for either week, and 0 (0%) sites from 0 states were at a high level (>80th percentile compared to levels recorded at that site between October 1, 2023 and March 2, 2024).

Risks to the General Public

The Current Risk to the General Public is Low

  • The detections of H5 viruses in wild birds, poultry, some mammals, and in two people in the United States do not change the risk to the general public’s health, which CDC considers to be low. However, due to outbreaks in domestic commercial and backyard poultry flocks, and infections in wild birds and some mammals, some groups of people with job-related or recreational exposures to birds or other H5 virus-infected animals, are at greater risk of infection. People with job-related or recreational exposures to birds or infected mammals should take appropriate precautions to protect against bird flu.
  • Due to widespread circulation of A(H5N1) virus in wild birds and poultry and sporadic infections in mammals, additional sporadic human cases would not be surprising.
  • Right now, the H5N1 bird flu situation remains primarily an animal health issue. However, CDC is watching this situation closely and taking routine preparedness and prevention measures in case this virus changes to pose a greater human health risk.
  • Signals that could raise the public health risk include multiple, simultaneous reports of human infections with A(H5N1) viruses following exposure to birds or other animals, or identification of spread from one infected person to another.
  • No known human-to-human spread has occurred with the contemporary A(H5N1) viruses that are currently circulating in birds in the United States and globally. In other countries, sporadic human cases of human infections with the A(H5N1) viruses most common in birds globally have been reported since 2022 mostly following exposure to infected poultry. During past A(H5N1) bird flu virus outbreaks that have occurred in poultry globally, human infections were rare. Globally since 2003, 23 countries have reported rare, sporadic human infections with A(H5N1) bird flu viruses to the World Health Organization (WHO). Monthly case counts are available on the WHO website.
  • The spread of bird flu viruses from one infected person to a close contact has occurred rarely in other countries in the past, and when it has happened, it has been limited and not sustained, and did not spread beyond close contacts.