A biological insecticide developed at Brazil's Oswaldo Cruz Foundation is an effective weapon against dengue because it does not harm human health or the environment, say researchers. It can be used in household water tanks and in pools, lakes and rivers, killing the larvae of the Aedes aegypti mosquito – which transmits the disease – within 24 hours.

“It is made from a protein in the form of a crystal, which paralyzes the mouth of the larva, and bacterial spores, which kill through intestinal infection,” project coordinator Elizabeth Sanches told Tierramérica.

For 50 liters of water, 350 milligrams of the bioinsecticide are dissolved. In rivers and lakes, which require dispensing pumps, the quantity needed is calculated according to flow or area. It is effective for 20 to 24 days, depending on rainfall.