In very poor countries, the family that has to walk miles to fetch drinking water from a well or a stream may be the lucky one. In many villages, the water source is a filthy pond trod by animals and people, or a mud puddle out next to the yam field.

As a result, about 6,000 people a day — most of them children — die from water-borne diseases.

Vestergaard Frandsen, a Danish textile company that supplies water filters to the Carter Center guinea worm eradication program and mosquito-killing plastic tarps to refugee camps, has come up with a new invention meant to render dangerous water drinkable.

The invention is called Lifestraw, a plastic tube with seven filters: graduated meshes with holes as fine as 6 microns (a human hair is 50 to 100 microns), followed by resin impregnated with iodine and another of activated carbon. It can be worn around the neck and lasts a year.