A rare human case of bird flu has been reported in Texas, after a person come into contact with cattle suspected of being infected. The announcement comes days after federal agencies said the virus had spread to dairy cattle across multiple states, including Texas. 

The Texas Department of State Health Services said the patient’s only experienced symptom was eye inflammation. The person, who has remained unnamed, was tested late last week and the Centers for Disease Control and Prevention confirmed the results over the weekend. The person is now being treated with the antiviral medication oseltamivir, which according to the Mayo Clinic can be used to treat influenza A and B, as well as the swine flu. 

Human cases of bird flu, otherwise known as H5N1, are known to produce a range of symptoms, including mild ones like eye infection and respiratory symptoms, to more severe, such as pneumonia and death, Texas officials said. 

The CDC said this is only the second time that a person in the U.S. has contracted the bird flu, which typically infects wild birds but can spread to domestic species. It has killed millions of birds across the world in its latest outbreak and has also spread to other mammal populations, killing sea lions, seals and even a polar bear. 

Last week federal agencies announced that dairy cattle are the latest animal group to have contracted a strain of the virus. Cattle in Texas, Kansas and Michigan are so far believed to be impacted, marking the first time that dairy cattle in the U.S. have dealt with this particular infection. 

Although it has spread to at least one individual, the Texas health department said it remains “extremely rare” for bird flu to spread from person-to-person. 

“Initial testing shows the virus has not changed in a way to make it more likely to spread among humans,” the department said. “DSHS is providing guidance to affected dairies about how to minimize workers’ exposure and how people who work with affected cattle can monitor for flu-like symptoms and get tested.” 

The last time someone in the U.S. contracted bird flu was in Colorado in 2022. That person was involved in slaughtering poultry presumed to be infected, and later reported feeling fatigued. According to the CDC, that person recovered after being isolated and treated with oseltamivir. 

“Human infections can happen when enough virus gets into a person’s eyes, nose, or mouth, or is inhaled,” the CDC said at the time. “People with close or lengthy unprotected contact (not wearing respiratory or eye protection) with infected birds or places that sick birds or their mucous, saliva, or feces have touched, may be at greater risk of H5N1 virus infection.”

What are the human symptoms of bird flu? 

According to a health alert sent out to clinicians, signs and symptoms of bird flu in humans are similar to that of a typical flu. They include a fever of at least 100 degrees Fahrenheit, or a feeling of being feverish, and chills, cough, sore throat, runny nose, headaches, fatigue, difficulty breathing, diarrhea, nausea, vomiting and seizures. What most notably separates it from the seasonal flu, however, is eye redness, otherwise known as conjunctivitis. 

“Because of this, healthcare providers including optometrists and ophthalmologists, should be aware of the potential of individuals presenting with conjunctivitis who have had exposure to affected animals,” the health alert says. “Reports of severe avian influenza A(H5N1) illness in humans have included fulminant pneumonia leading to respiratory failure, acute respiratory distress syndrome, septic shock, and death.” 

Officials have emphasized that risk to general public remains low, and that practicing good hygiene can help prevent the spread of this and many other illnesses. 

“People can protect themselves against flu by washing their hands often, covering their coughs and sneezes, not picking up dead birds and animals, and staying home if sick,” the health alert says.

Because dairy cattle have been impacted, officials have also warned against consuming raw unpasteurized milk, which can make humans ill even if it is not infected with bird flu. Milk purchased in stores is required to be pasteurized and is safe to drink, officials said.