Bird Flu Update: Cases Rise in US, Colorado Reports Novel Infections

As of March 1, 2026, the United States is experiencing a widespread outbreak of H5 bird flu, affecting both wild birds and poultry, with recent cases detected in dairy cows and sporadic human infections among workers in the poultry and dairy industries. Even as the current public health risk remains low, health officials are closely monitoring the situation and implementing surveillance measures.

Current Situation: A(H5) Bird Flu in the US

The Centers for Disease Control and Prevention (CDC) is actively tracking A(H5) bird flu activity through its influenza surveillance systems. As of February 18, 2026, the virus is widespread in wild birds globally and causing outbreaks in poultry. Recent outbreaks have likewise been identified in U.S. Dairy cows, leading to a slight number of human cases.

CDC streamlined A(H5) bird flu updates with routine influenza data updates on July 7, 2025. Data on the number of people monitored and tested for bird flu are available at A(H5) Bird Flu Surveillance and Human Monitoring | Bird Flu | CDC and are reported monthly. USDA data on highly pathogenic avian influenza (HPAI) detections in animals can be found on USDA’s website.

Human Cases in Colorado and Nationwide

Colorado has reported multiple cases of H5 bird flu in poultry workers. As of July 19, 2024, six human cases were linked to exposure to infected poultry, with workers experiencing mild symptoms such as pink eye and respiratory issues. All exposed workers have been offered antiviral medication. On July 25, 2024, the US had a total of 13 human cases in 2024.

Three additional human cases were confirmed in Colorado on July 25, 2024, bringing the total number of human cases associated with poultry outbreaks in Colorado to nine. These new cases occurred among workers at a commercial egg layer operation in Weld County, Colorado. All three individuals experienced mild illness and were offered the antiviral drug oseltamivir.

Genetic sequencing of samples from Colorado cases indicates the virus is closely related to the first human case discovered in Michigan, and shows no signs of antiviral resistance, according to the CDC. CNN reported this finding as reassuring.

Since April 2024, there have been 10 reported human cases of avian influenza in the US, four linked to exposure to sick dairy cows and six connected to infected poultry. CNN

CDC Recommendations and Risk Assessment

The CDC’s current risk assessment for the general public remains low. But, human infections are concerning due to the potential for severe disease and the possibility of a pandemic if the virus were to change and spread easily between people. To date, no genetic changes have been observed that would increase human-to-human transmission.

The CDC recommends the following precautions:

• Avoid close, long, or unprotected exposure to sick or dead animals, including wild birds, poultry, and other animals.
• Avoid unprotected exposure to animal poop, bedding, unpasteurized milk, or materials contaminated by potentially infected animals.
• Follow recommended worker protection and personal protective equipment (PPE) guidelines.

A CDC field team is assisting with the outbreak investigation in Colorado, including assessing compliance with PPE recommendations.

Looking Ahead

The CDC continues to monitor the H5 bird flu situation closely and will update its recommendations as needed. Ongoing investigation and analysis of virus sequences will help determine if any changes in the risk assessment are warranted. Staying informed and following public health guidance are crucial steps in mitigating the risk of infection.