House dust mites like to live in dark and damp environments and we find a lot of them at the base of the carpet

Dr Jill Warner, Southampton University

One in five children in the UK now suffers from asthma.

Dr Warner said up to 100,000 dust mites can live in just one square metre of carpet alone.

The droppings of these tiny creatures are believed to stimulate asthma and other allergic responses.

Carpets also harbour material from pets such as cats and dogs which is also thought to be a leading cause of allergy.

Dr Warner told the BBC: "House dust mites like to live in dark and damp environments and we find a lot of them at the base of the carpet.

"When you consider that each one of them produces 20 faecal particles every day, and that is where we find the allergen then there are an awful lot in a house full of fitted carpets."

Cleaning ineffective

The study found no amount of cleaning would get rid of the allergens - the mites are able to withstand the suction power of most vacuum cleaners.

Only the removal of carpets cut allergens to 10% - a level which could reduce asthma symptoms and cut the risk of developing sensitivity, the study found.

Dr Warner's report was published to coincide with the launch of the Healthy Flooring Network, an alliance of organisations concerned about asthma and allergy who commissioned the study.

There are far fewer mites in carpets in the average home than there are in beds

Dr John Maunder, Medical Entomology Centre, Cambridge

Members include the National Eczema Society, Action Against Allergy and the Women's Environmental Network.

The Network has called for householders to put alternatives to carpets in their homes, including wood, laminate and linoleum floors.

Helen Lynn, health co-ordinator of the Women's Environmental Network, said: "This report shows that getting rid of carpets could radically reduce the amount of allergens in our homes.

"Where small children are concerned this simple act could save them from a life's suffering with allergies and breathlessness."

Claim disputed

However, Dr John Maunder, director of the Medical Entomology Centre at Cambridge, said beds were more likely to blame for asthma than carpets.

He told the BBC: "There are far fewer mites in carpets in the average home than there are in beds.

"The allergen, although it may be present in enormous quantity in carpets, is not in a physical form where it easily becomes airborn again.

"The danger with asthma is breathing in the allergen. The allergen particles in a bed are very much more readily made airborn - just turning over in bed is enough."

Dr Maunder said effective ventilation was a crucial factor because it deprived mites of the humidity they required to thrive.