California reports first suspected H5N1 bird flu patient, amid fears the virus is spreading between humans for the first time

A dairy worker in California tested ‘presumptive positive’ for bird flu, possibly becoming the 15th person in the US to contract the disease.

The unknown patient works at a dairy farm where there is currently an outbreak of bird flu, H5N1, among the livestock. The person experienced mild symptoms, involving only conjunctivitis or red eyes.

The local health department was notified and tested the employee for the virus, which was presumed positive.

A sample is now being sent to the CDC for further testing.

The latest possible case of bird flu is suspected in a California dairy worker (stock image)

The patient, the first in California, is being treated with antiviral medications and is in isolation at home.

Fears about the spread of bird flu are increasing as the virus has been diagnosed for the first time in a patient in Missouri who had not come into contact with sick birds, livestock or other animals.

The worst-case scenario is that the patient contracted it from another person and the virus started spreading quietly between Americans.

While this is unlikely, Dr. Kruitka Kuppali, spokesperson for the Infectious Disease Society of American and former World Health Organization official, warned last month, “This is how pandemics start.”

The Missouri case was discovered through the state’s seasonal flu surveillance system, which tracks flu activity based on testing of symptomatic patients.

Another theory is that the Missouri patient drank raw milk contaminated with the virus.

Raw milk is becoming increasingly popular, and research has shown that H5N1 particles can linger in milk for up to five weeks if it is stored in the refrigerator, according to the National Institutes of Health (NIH).

The CDC reported that since March 2024, the agency has monitored more than 4,900 people exposed to animals infected with H5N1 and has tested more than 230 people.

So far, fourteen people have tested positive, but because bird flu does not always cause symptoms, there may be more sick people who never get tested.

In March, a Texas dairy farmer tested positive for the virus and experienced similar symptoms to those reported in the patient from California’s Central Valley: conjunctivitis.

This is the first photo of the Texas farm worker infected with bird flu. The infection started in the right eye and then spread to the left

A case report describing the man’s illness stated that the patient also suffered from a subconjunctival hemorrhage, a hemorrhage just below the conjunctiva, or a clear surface covering the white part of the eye.

Scientists also noted that a watery fluid was flowing from the right eye.

Other symptoms patients may experience include coughing, sore throat, runny or stuffy nose, headache, and body aches or muscle aches.