Air Date: Week of September 23, 2005

Living on Earth's Emily Torgrimson reports on efforts to use guppies in the battle against dengue fever.

Transcript

TORGRIMSON: A day in the life of a guppy: cruise ‘round the plastic castle, swim up to the surface for pellets, check out the bejeweled mermaid on the far side of the tank, and now, help fight a dengue epidemic in India.

In recent weeks, dengue fever has killed dozens of people and affected hundreds in West Bengal, India. Dengue is a mosquito-born disease that causes fever, nausea, headaches, and, if it is not treated, death. But health officials in West Bengal have released thousands of guppies into waters where mosquitoes breed.

Mosquitoes there are proving resistant to many pesticides, so officials are relying on the help of guppies and gambusia - a fish commonly known as “the mosquitofish” because of its ability to eat its weight in mosquito larvae a day. And both fish species can survive where water quality is poor, like stagnant ponds or shallow bodies of water.

Critics of the method say guppies and gambusia often grow to outnumber native species of fish – they attack other fish by nipping at their fins, eyes, and preying on their eggs. There’s no indication yet of the immediate effect the fish are having on the dengue epidemic, or other mosquito-born illnesses, like encephalitis and malaria.

That's this week's Note on Emerging Science. I'm Emily Torgrimson.