Sitting target? Mosquito larvae develop in pools of water

Flickr/Alvaro Rodriguez

The humble spade could be a major tool in the fight against malaria, according to a computer model that has found that simply filling in puddles of water could halt malaria-carrying mosquitoes in their tracks.

The model, developed by researchers at the Massachusetts Institute of Technology (MIT) in the United States, is based on the interactions that take place between humans, mosquitoes and the environment — particularly bodies of water — for malaria infection to take place.

It could be used to evaluate the impact of anti-malaria interventions anywhere, provided the correct region-specific data is inputted, the authors say.

Researchers created the model using field data from a region in Niger, where they looked at factors such as numbers of larval and adult mosquitoes, the type of malaria-carrying species of mosquito, and the characteristics of pools where the mosquitoes breed.

They tested it in the village of Banizoumbou in southwestern Niger — where they found that a 16 per cent increase in rainfall increased mosquito numbers by 132 per cent, which it is assumed would then go on to affect malaria rates. This was backed-up by field data from Banizoumbou.

They also evaluated the impact of different interventions and found that eliminating pools of standing water by filling them in, or draining the land so pools don't last long enough for mosquitoes to mature, can be effective strategies.

The authors also say that spreading seeds from the neem tree, which grows locally, in the pools twice a week can reduce the mosquito population by about 50 per cent. The seeds contain a chemical that kills mosquito larvae.

"This model is an appropriate tool for testing intervention strategies to limit malaria transmission even before implementing them, and for simulating the impact of climate change on malaria transmission," Elfatih Eltahir, professor of civil and environmental engineering who led the research project at MIT, told SciDev.Net.

He adds that the environmental management approaches indicated by the modelling — such as using neem as a larvicide — are low cost and effective for combating malaria in developing countries.

Morad Ahmed Morad, a professor of medicine at Tanta University, Egypt, welcomed the model and called for the establishment of a database of simple technologies that could be used to prevent and treat malaria.

This could be used as a guide for scientists and policymakers in formulating simple, applicable and cost-effective strategies for dealing with malaria in their regions, he said.

The research was published in Water Resources Research in December.

Link to abstract in Water Resources Research