CDC data unveils potential undetected spread of avian influenza in cattle and humans, raising concerns about the virus’s reach and surveillance needs.
At a Glance
- CDC analysis suggests bird flu may have spread undetected in cows and people
- Three out of 150 cow veterinarians had antibodies against bird flu without symptoms
- Systematic surveillance recommended for dairy cattle, milk, and exposed humans
- Bird flu has infected nearly 70 individuals in the U.S. since April 2024
- CDC states current risk to the general public remains low
Undetected Spread of Avian Influenza
The Centers for Disease Control and Prevention (CDC) has released new data suggesting that highly pathogenic avian influenza may have spread undetected in cows and people across the United States. This revelation comes as part of an ongoing investigation into the virus’s potential to cross species barriers and poses significant implications for public health and agricultural sectors.
A recent study conducted by the CDC found that three out of 150 cow veterinarians tested positive for antibodies against bird flu, indicating they had been infected without showing symptoms. Alarmingly, two of these veterinarians had not been exposed to sick animals, and one was not even in a state where bird flu had been detected in cattle. This discovery suggests the virus may have a wider geographical spread than previously thought.
Calls for Enhanced Surveillance
In light of these findings, the CDC is recommending a more comprehensive approach to monitoring the situation. The agency emphasizes the need for systematic surveillance to rapidly identify the bird flu virus in dairy cattle, milk, and humans who come into contact with cattle.
“These findings suggest the possible benefit of systematic surveillance for rapid identification of [the bird flu] virus in dairy cattle, milk, and humans who are exposed to cattle to ensure appropriate hazard assessments,” the CDC stated.
This proactive stance is crucial for accurate risk assessment and timely intervention to prevent potential outbreaks.
CDC confirmed a 2nd H5 bird #flu human infection in the U.S. associated with exposure to infected dairy cows. Based on information so far, CDC believes risk to the public continues to be low, but people with exposure to infected animals are at higher risk: https://t.co/H765EvEyAq pic.twitter.com/fd0HUd93nt
— CDC Flu (@CDCFlu) May 22, 2024
Impact on Human Health and Agriculture
While the CDC maintains that the current risk to the general public remains low, the situation has already had significant impacts. Since April 2024, nearly 70 individuals in the U.S. have been infected with bird flu, including one reported death in Louisiana involving a man over 65 with preexisting health conditions.
“The risk of acquiring bird flu to the general U.S. population is low. The best way to prevent bird flu is to avoid direct contact with wild birds or sick or dead poultry or other animals,” state health officials said.
The poultry industry has been hit particularly hard by the avian influenza outbreak. Millions of chickens have been culled in an effort to contain the virus, leading to a sharp increase in egg prices. In January 2025, egg prices reached a record high of $4.95 per carton, prompting some retailers to limit purchases.
