While bird flu is rare, the Centers for Disease Control and Prevention reported 61 human cases this year. Only three were linked to people working on or near dairy and poultry farms. The agency also included two more cases: one found in other animal exposure, and the other could not be confirmed.

CNN reported that the current bird flu outbreak in the U.S., identified as H5N1, is only found in infected birds. The virus attaches to sialic acids — sugars on the surfaces of cells. Once bound, the virus begins invading the cells and spreading to the respiratory tracts of birds. However, the virus can also spread to other animals, including dairy cattle, a trend that began in 2022.

What is the animal-to-human likelihood of contracting the virus?

According to a recent study published in Science Journal, the bird flu virus has caused only 30% of human fatalities since it first emerged. While the likelihood of animal-to-human transmission remains low, a single glutamine-to-leucine mutation is enough for the virus to spread from animals to humans, leading to what the paper described as a “human pandemic risk.” That said, there is no indication of when this may occur, or even at all.

A 65-year-old man from Louisiana has been hospitalized, marking him as the first “severe” case of the H5N1 bird flu virus. According to The Sun, people who contracted the disease have reported mild symptoms, including conjunctivitis and a sore throat. The most recent U.S. case is linked to the man’s backyard, which contained birds, not dairy cattle.

On Wednesday, California Gov. Gavin Newsom declared a state of emergency after more than 300 herds tested positive for the virus in the past 30 days, NPR reported. The cases detected were among dairy cows on farms in Southern California, which are now closely monitored as the state continues to work through the outbreak.

“This proclamation is a targeted action to ensure government agencies have the resources and flexibility they need,” Newsom said in the statement obtained by NPR.

Is there human-to-human spread in the U.S.?

NPR reported that there had been no human-to-human transmission of the virus in California or elsewhere in the U.S. However, scientists caution that the rise of bird flu in dairy cattle could lead to spillover into humans, potentially causing dangerous mutations due to the virus’s high contagion rate.

Dr. Demetre Daskalakis from the CDC stated that most cases are still linked to sick and infected animals. However, several cases in the U.S., particularly in California and Missouri, remain untraceable to infected animals.

“Infections without a clear source of exposure do occur, neither these cases nor the cases with known animal or animal products exposure have resulted in human to human transmission,” Daskalakis said, per NPR.

How can I prevent bird flu?

The Cleveland Clinic and CDC reported a list of ways to protect against and reduce the risk of contracting the bird flu virus.

– Wear protective gear, such as gloves, masks and goggles, when working around birds, wild birds and livestock, especially on farms with birds and other animals.

– Wash your hands when handling these animals and visiting places with birds and other farm animals.

– Don’t work with animals who are sick or have been exposed to the influenza virus.

– Don’t touch or drink unpasteurized milk.

– Eating undercooked poultry or beef can increase your chances of contracting the illness. It usually comes from uncooked poultry, and poultry products like blood have led to a small number of cases across the U.S. To lower your chances, preparing food correctly and separating raw and cooked foods is required to prevent cross-contamination.