New studies in Cambodia and Laos have shown a way to use fish to limit dengue fever.
Dengue, spread by mosquitos, causes 20,000 deaths in the world each year, and threatens many Pacific countries.
The studies in the two countries, with the support of the Asian Development Bank and the World Health Organisation, showed that leaving two guppy fish in drinking water tanks significantly lowered the mosquito larvae without affecting the water quality.
The ADB health specialist Gerard Servais says it's not a silver bullet, but could work wherever there are water tanks and other containers holding enough water for fish to survive.
He says the small-scale studies looked at 30 villages with around 30,000 people in total.
"It has proven that less than five percent of the tanks are infected. Once there is a guppy fish in the tank all the mosquito larvae disappear. If you can find the larvae it's because the family or the community didn't put the guppy fish inside."
Gerard Servais.
