Black lice are more typically known as head lice, which is a type of tiny parasite that prefers to stay on the scalp of humans for warmth. Adult head lice are about the size of a sesame seed and drink tiny amounts of blood for nourishment, notes KidsHealth. Their presence can cause itchy skin irritation, which seems to worsen at night.
Even though head lice are not known to transmit any disease, it is possible for their host to develop secondary skin infections due to scratching too frequently and too hard. Head lice do not pick their hosts based upon cleanliness, age, ethnicity or hair type. They do not spread by jumping or flying, but rather by people's heads touching or the sharing of bedding, hats, combs and hair accessories, according to the Centers for Disease Control and Prevention.
Lice spread most easily among children, especially at school. Once an infestation takes place, lice can survive on a human head for as many as 30 days and lay as many as eight eggs per day, reports KidsHealth. There are a number of over-the-counter treatments for getting rid of the insects available in almost any drug store. It is important to follow their instructions precisely to prevent spreading and reinfestation, recommends the Alabama Cooperative Extension System.