The first image of a Texas farm worker infected with bird flu from a cow shows he suffered bleeding in his eyeballs.

It is thought to be the first known case of mammal-to-human transmission and comes as the Centers for Disease Control and Prevention (CDC) warned bird flu (H5N1) viruses “pose pandemic potential.”

The dairy worker attended a hospital in March after experiencing painful red, weeping eyes with burst blood vessels.

His eyes began to swell up though he had no fever and an examination showed his lungs were clear, according to a letter published in the New England Journal of Medicine on Friday.

The journal also contained the image of the infected man, alongside the scientific term for his eye condition: conjunctivitis with subconjunctival hemorrhage.

READ MORE: CDC warns bird flu ‘poses pandemic potential’ as fears of human infection surge

Lara Anton, a spokesperson for the Texas Department of State Health Services, said it’s because the infected dairy worker “did not disclose the name of their workplace” during a visit to a field office for testing.

According to the report, the worker did not wear protective eye goggles or a face mask that could have prevented the infection.

Bird flu had been circulating in cows for an estimated four months before it was confirmed by labs in late March, according to a new report released by the US Department of Agriculture (USDA) on Thursday.

Since then, at least 36 dairy cow herds have been infected across nine US states, including Idaho, South Dakota, Colorado, Kansas, New Mexico, Texas, Michigan, Ohio, and North Carolina.

While traces of the virus have been found in samples of milk from grocery stores, the Food and Drug Administration (FDA) has said pasteurized milk remains safe to drink.

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