There are no confirmed cases
of a human passing bird flu to another human.
People can catch the disease if they have close contact with live infected birds.
One way this happens is that sick birds pass the virus out of their bodies in their droppings. As these dry they can be trampled on by people or other birds. The droppings are ground into a dusty powder and if humans breathe in the dust they might get bird flu.
The first known case of a human getting bird flu was in 1997, in Hong Kong.
So far it's thought that all the people who have caught bird flu had been very close to live chickens that were carrying the virus. They worked on farms or had been to markets where live animals were for sale.