Mosquitoes that carry the deadly malaria parasite might be breeding right outside your front door. Researchers say methods of controlling them can be simple, inexpensive and very effective, especially when the community gets involved.
More than 300 million people worldwide will contract malaria this year and more than one million will die from it. It is one of the greatest public health challenges in the developing world. But University of Durham researcher Ulrike Fillinger says in places where malaria is widespread, many people do not know how they get the disease.
"They do know, OK, we get malaria when it rains. So very often you hear people telling you, you shouldn't stand in the rain otherwise you will catch malaria," he explained. "So they kind of know it has to do with the rainy season. But they don't know it's actually the mosquito that proliferates in the rainy season because you have a lot of breeding sites."
Experts say malaria-carrying mosquitoes can breed in almost any pool of standing water, from riverbanks and ponds to footprints and hoofprints.
But insect control expert Josephat Shililu says it is the manmade breeding places that are the biggest problem, even in areas where rain is only seasonal. He found that in Eritrea, natural breeding places dry up during the seven-month dry season.
"But what keeps the mosquito population going are the man-made breeding sites, such as the water collection points, the irrigation the dams, the ponds that are dug to keep water for animal drinking," he said.
He says in Eritrea, people tend to overuse water when they have it. Crops are often overirrigated and left with pools of standing water where mosquitoes multiply. Water leaking out from pumps or dams can also form puddles in which malarial mosquitoes love to breed.
Ms. Fillinger says according to her studies in Kenya, even holes dug to burn trash or mix concrete become mosquito havens when it rains.
"The man-made sites are really much more frequent than all the natural sites and therefore a big problem," she said. "And you could easily solve that problem just by education. People often do not associate that that hole in front of their door is really causing the disease of their children."
Ms. Fillinger says rather than lecturing communities on what they should and should not do, she and others have shown them that young mosquitoes, called larvae, were hatching in those holes on their doorsteps.
"We went out with what we call a mosquito dipper, kind of a spoon. You go around and you dip in all the water bodies around and you really show the mosquito larvae to the community," she explained. "You might put the larvae in a glass and let them emerge to adult, something that those people have never seen. And that makes such an impact because then suddenly they do understand what is happening just in front of their doorstep."
Ms. Fillinger and Mr. Shililu are trying out experimental programs to get communities involved in controlling mosquito larvae. Community members are trained to find and drain water-filled holes, irrigation channels, ditches, and so on. Those that can not be drained are treated with insecticides to kill the larvae.
Mr. Shililu says preliminary studies are promising. Mosquito numbers come down substantially. And the programs do not seem to cost much. "So far, we have only rough figures. And the rough figures show that actually you need very little funds to actually sustain and keep larval control moving. And this relies on the communities if they are able, if they are willing to participate."
Mr. Shililu says he hopes the trial studies will convince communities that they can make a difference in keeping mosquitoes in check. And he hopes they will keep it up long after the trials are over.
"When you do a trial like what you are doing, people are very enthusiastic," he said. "But (after) you've left them alone, we still don't know how they'll carry it on. But we hope, we are very hopeful there will be a continuation of the process."
One important question researchers have not answered yet is how much mosquito control is needed to reduce the number of people who actually get malaria. Such studies are being planned. In the meantime, communities that drain their puddles can at least look forward to fewer itchy mosquito bites.