<human>: I've heard that there is a bird flu. What is the difference between a bird flu and the flu that affects humans?
<bot>: Bird flu is a specific type of influenza virus that infects birds, while the flu that affects humans is caused by several different types of viruses. The main difference between the two is that bird flu primarily affects birds, whereas human flu can affect people as well as other animals, such as pigs, horses, and dogs.