Two Michigan farm workers have been diagnosed with avian, or bird, flu, after an outbreak in dairy cows in the United States. The virus has also been detected in domesticated chickens, leading to the slaughter of flocks across the nation.

We asked Teena Chopra, M.D., M.P.H., professor of Internal Medicine, Infectious Diseases, for the Wayne State University School of Medicine, to answer questions about bird flu, its effects on humans and how worried we should be about transmission from animals to humans.

Dr. Chopra serves as the corporate medical director of Hospital Epidemiology, Infection Prevention and Antibiotic Stewardship at the Detroit Medical Center, Wayne State University. One of the founding leaders of the WSU Center for Emerging and Infectious Diseases, she championed the mammoth task of leading COVID-19 pandemic efforts for Wayne State University and the DMC. She serves on the president’s COVID Task Force and on the President’s Public Health Committee. She has appeared in countless media and print interviews, including CNN, FOX, NPR and TIME magazine. She is a fellow of the Executive Leadership Academy of Medicine.

What exactly is “bird flu?”
Recent reports have highlighted cases of avian influenza among dairy cows in Texas, with three human cases, two in Michigan. The strain, a highly pathogenic avian influenza virus A (H5N1), or HPAI, has been around for more than two decades, primarily affecting birds with high contagiousness and fatality rates. While transmission to humans is possible (typically through direct contact with infected birds, such as during hunting), efficient human-to-human spread has not been observed.

How worried should I be about Avian flu? How did it jump to cows and then to humans?
Given no evidence of human-to-human transmission, this is not a worrisome situation. Unless you work closely with wild birds or animals, your risk is minimal.

While transmission to humans is possible (typically through direct contact with infected birds), efficient human-to-human spread has not been observed. However, the virus's ability to mutate increases with each interspecies transmission event.

Recent developments indicate heightened activity:
Avian infections declined from 2016 to 2022. Since 2022, the United States. has faced its most significant and prolonged avian flu outbreak, initially among wild birds and then spreading to domestic poultry, causing shortages of eggs and price hikes.
Notably, avian flu cases in mammals have emerged globally, affecting seals, bears, mountain lions and foxes.

Authorities reported HPAI infections in cows across multiple dairy farms in five states, with laboratory analysis revealing:

The virus strain infecting cows matches the one affecting birds, indicating interspecies transmission.

Despite familiarity with the virus, no significant mutations have been detected so far, suggesting limited human-to-human transmission potential. Unlike pigs, which serve as dangerous hosts due to their possession of both avian and human receptors, cows do not exhibit similar characteristics, reducing the risk of becoming influenza "mixing vessels."

Have there been rounds of bird flu in humans before, and if so, what happened?
While it can infect humans, the virus has never been able to spread efficiently among humans.

What are the symptoms?
In the three reported human cases, mild symptoms, including red eye and mild respiratory symptoms like cough and congestion, were noted.

How do I tell if I have it? Is there a specific test?
Yes, there is a specific test that can detect the virus.

Can I get it from eggs, milk or the meat of infected animals?
You cannot get avian flu from eating poultry or eggs or meat. Pasteurization is a critical step in ensuring the safety of milk in commercial supply chains. It helps eliminate harmful pathogens, including viruses like influenza, making the milk safe to consume. Raw milk, on the other hand, hasn't undergone this pasteurization process and can pose significant health risks due to potential contamination with bacteria, viruses and other harmful microorganisms. It's always best to stick with pasteurized milk from reputable sources to minimize the risk of foodborne illnesses.

What can I do to avoid catching Avian flu?
Right now, there is nothing to do if you are not in close contact with wild birds or cattle.

Is the annual flu vaccination protection against Avian flu?
There is no vaccine currently, but it can be quickly made if there were any evidence of human-to-human transmission.