A headlice comb that attaches to a vacuum cleaner has been developed by a Danish schoolmaster.

He claims it is far more efficient than combing by itself, or insecticide-laden shampoos.

The device is simple enough - the comb links to the nozzle at the end of the vacuum cleaner and sucks in any lice and eggs revealed by a thorough combing session.

The unwanted visitors are deposited on a filter for easy disposal.

Carsten Hoegholm, who developed the invention, told the BBC: "What we have made here is much more efficient when you are combing hair for lice.

"The problem with the other way of doing it - using chemicals in shampoos - is that lice have developed resistance to these."

Schoolyard problem

Lice are a perennial problem in schools across Europe, with some classes suffering multiple outbreaks in a single school year.

A single louse can lay dozens of eggs, called nits, at the rate of three a day.

They are grey in colour, although they can take on the colour of the hair to which they are attached.

They grab hold using large hooked limbs, and cannot fly or jump, relying on direct hair to hair contact to pass from host to host, although they can be transferred by head contact with contaminated bedding or furniture.

While their bloodsucking activities do cause itching, it is not dangerous in itself, although the host's scratching activity can lead to secondary infections of raw areas of scalp.

Resistance to traditional insecticide shampoos has been increasing steadily over recent years.

Regular head combing is recommended by many experts, although this will not prevent reinfection.

More recent work has centred on find new, non-toxic ways to rid the hair of nits or lice.

One approach is looking at ways of dissolving the bond that locks each newly-laid nit onto the hair shaft ready for hatching.