Do head lice carry or transmit disease?

While many have thought head lice to be only a nuisance, recent scientific study refutes this notion. DNA technology shows head lice to be the same species as the notorious body louse which has long been associated with diseases such as typhus and relapsing fever. The potential for disease transmission via the head louse should not be underestimated. Head lice can also be an annoyance because their presence may cause itching and loss of sleep. Sometimes the itching can lead to excessive scratching that can sometimes increase the chance of a secondary skin infection.