Fleas can be a big deal because they are parasites which can spread disease, as well as cause misery for cats, dogs, and other animals around the world.
When a flea finds a host animal, it will live directly on the body of that animal and continually bite it in order to feed on its blood.
The flea needs this blood meal in order to reproduce, and it can lay up to 20 eggs per day, giving it an incredible ability to reproduce and multiply.
Flea bites cause an allergic reaction in most animals and humans, causing a raised red bump on the surface of the skin that is quite itchy and swollen.
These bites can become dangerous when the surface of the skin is broken by scratching or biting at them, because it can lead to infections which can spread to other parts of the body.
It is very difficult if not impossible to get rid of a flea infestation without the use of modern methods of flea control.