They are the bane of many parents’ lives.
Not only do headlice cause incessant itching, but treating them is an ordeal in itself, with tears, tantrums and products often potent enough to knock you out.
And as the schools go back – and we hit peak nit season – hundreds of thousands of youngsters will be affected.
Why? Because the small insects are highly adapted to one type of environment: hair on a human’s head – especially primary school-aged children.
Infuriatingly, in the battle of human’s vs headlice, it’s the parasite that’s winning.
Scientists have warned that lice are becoming increasingly resistant to products – leaving parents with fewer options than ever.