Scientific Asia: The CDC confirmed two farm workers in California had contracted avian influenza.
Latest Update (July 2026)
What began in 2024 as a handful of infections among US farm workers has become the largest H5 bird flu outbreak in US animals and people to date. From 2024 through May 2026, health authorities identified about 71 human cases of H5N1 avian influenza in the United States, with two deaths, according to the CDC and the American Academy of Ophthalmology (AAO, 2026).
Despite the higher numbers, the core public-health message has not changed: risk to the general public remains low, and no person-to-person spread has ever been identified. Reassuringly, no new US human cases have been reported since mid-February 2025 (CDC, 2026). The developments below explain how the situation evolved after this story was first published, when the count stood at 16 cases.
The Original Report (October 2024)
The CDC confirmed that two farm workers in California had contracted avian influenza. The United States Centers for Disease Control and Prevention confirmed that two farmworkers in California had tested positive for H5 avian flu. The California Department of Public Health confirmed the state’s first two likely human cases just hours after the announcement. Both workers submitted samples to the CDC for additional testing.
According to health officials, the two workers who contracted bird flu had not been in contact with each other. They worked on separate dairy farms in California, and both farms had confirmed cases of H5N1 avian influenza in their cattle. Both individuals experienced only minor symptoms.
In both cases, the main symptom was red eyes, or conjunctivitis, indicating that the infection likely entered through the eyes. This can happen if contaminated milk splashes onto the face, or if a person rubs their eyes after touching virus-contaminated hands. Neither worker experienced respiratory symptoms or required hospitalization.
At the time, health officials said there was still little risk to the general public, though farm workers faced higher risk. The CDC advised workers to use personal protective equipment such as gloves, a mask, and goggles to reduce their risk of infection.
As of October 2024, health authorities had reported 16 human cases of bird flu in the United States that year, including the two most recent cases in California.
Bird flu human cases in the US, as of October 2024:
- Texas: 1
- Michigan: 2
- Colorado: 10
- Missouri: 1
- California: 2
At that point, exposure to sick or infected dairy cows accounted for six of the 16 documented human cases, while nine cases involved exposure to contaminated poultry.
How the Story Developed (Late 2024 to 2026)
In the months after the original report, the outbreak reached several new milestones.
November 2024: first child case. The first US H5N1 infection in a child was reported in California. The child had mild symptoms and recovered (CDC; AAO, 2026).
January 6, 2025: first US death. The CDC reported the first H5N1-related death in the United States, in Louisiana. The patient was over 65 with underlying medical conditions and had been exposed to backyard and wild birds. This was the most serious turn in the US outbreak up to that point (CDC, 2025).
Early 2025: further cases. The CDC confirmed additional infections in a Nevada dairy worker, an Ohio poultry worker, and a Wyoming backyard flock owner. By early 2025, the US total had reached about 70 human cases across 2024 and early 2025 (CDC, 2025).
Mid-February 2025 onward: a pause. After mid-February 2025, no new US human cases were reported. As of mid-2026, that pause has held, and the cumulative US total stands at about 71 cases with two deaths (CDC; AAO, 2026).
July 2025: reporting simplified. Reflecting the calmer situation, the CDC folded its bird-flu updates into routine monthly influenza reporting on July 7, 2025 (CDC, 2025).
Outbreak Timeline at a Glance
| Date | Development |
| March 24, 2024 | First US dairy-cow H5N1 infections confirmed |
| October 2024 | US total reaches 16 human cases; two California dairy workers confirmed |
| November 2024 | First US child case (California) |
| January 6, 2025 | First US H5N1 death (Louisiana) |
| Early 2025 | Further cases in Nevada, Ohio, and Wyoming; total nearly 70 |
| Mid-February 2025 | Last reported US human case to date |
| May 2026 | The cumulative US total is about 71 cases, with two deaths |
Sources: CDC; American Academy of Ophthalmology (2026).
The Global Picture
Outside the United States, sporadic H5N1 cases and deaths continued through 2025 and 2026, reported mainly in Cambodia, India, Bangladesh, and Mexico. Most involved direct contact with sick or dead poultry. Notably, many of these cases involve a different viral clade than the strain circulating in US dairy cattle. Globally, since 1997, 25 countries have reported more than 1,000 human H5N1 infections, with roughly 48% of them fatal, which is why health agencies continue to watch the virus closely even as the immediate US public risk stays low (CDC, 2026).
CDC Guidance
The CDC’s guidance for people who work with animals has remained consistent throughout the outbreak:
- Avoid consuming unpasteurized (raw) milk and cheese.
- Avoid contact with wild birds and sick or dead animals.
- Wear protective gear such as masks, gloves, and goggles when working with dairy cows, poultry, or other animals that might carry bird flu, and take extra care around the animals, their milk, or anything that could be contaminated.
- See a healthcare provider and contact your local health department if you feel sick after being near infected animals.
Bird flu symptoms include red eyes (conjunctivitis), fever, cough, sore throat, runny or stuffy nose, and muscle aches.
Sources
- CDC, H5 Bird Flu: Current Situation (2026)
- CDC, H5N1 Response Updates and case summaries (2025 to 2026)
- American Academy of Ophthalmology, Novel H5N1 Bird Flu Outbreak Clinical Statement (2026)
- California Department of Public Health (2024)
