Head lice are becoming immune to treatments, scientists have warned.
Research suggests nits are developing a high level of resistance to commonly used over-the-counter remedies, meaning they are becoming even harder to shake off.
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The Mirror reports that researchers from Southern Illinois University found lice have developed resistance in at least 25 US states.
They found many of the insects tested positive for genetic mutations; affecting the nervous system of the lice and desensitising them to treatments.
Lice are particularly common among primary school age children and are spread by head-to-head contact. The lice feed on blood from the scalp of the person they have settled on. The bites can cause persistent itchiness and inflammation of the scalp.
Common treatments include using lotions and sprays on the affected area, or using a specially designed lice comb.
