* Dander is the dead skin cells that cats shed. This protein attaches to the skin flakes and is easily spread through the air.
* Saliva contains Fel d 1, and it can be spread when cats lick themselves or groom their fur.
* Urine also contains the protein, and it can be released into the environment when cats use the litter box.
It's important to note that even though humans are allergic to Fel d 1, not all cats produce the same amount of this protein. Some cats produce more Fel d 1 than others, making them more likely to trigger allergies in humans.