Lice are parasites members of the order Phthiraptera, that live off of blood and are the most known parasites of humans, living in their hair, really close to the scalp. They can also easily infest birds and other mammals, and can be vectors of diseases, such as typhus. Out of almost 5,000 identified species, 4,000 of them affect mostly birds, and 800 usually infest mammals.
