An outbreak of bird flu has many wondering exactly how the disease is spread -- and how easy or difficult it is for people to get the virus from infected animals.
In the past, bird flu has caused serious and sometimes deadly infections in people and has long been on the World Health Organization’s list of viruses with the potential to start a pandemic.
The current outbreak has led to the first known case of transmission between a cow and a human -- when a Texas farm worker caught it.
Previously, the virus had mostly been passed to humans through close contact with wild birds or infected poultry.
The WHO says that while human infections are rare, they can be deadly.
Between 2003 and 2024, 889 H1N1 infections were reported, and a little more than half of those were deadly.
Human infections generally happen through direct contact with a person’s eyes, nose or mouth -- or when the virus is inhaled as droplets as small aerosol particles.
Most human bird flu infections happen after close, prolonged and unprotected contact with infected birds.
Severe infections can lead to pneumonia and acute respiratory distress syndrome.