Hesperian Health Guides
Community Mosquito Control
Mosquitoes lay eggs in standing water. It takes about 7 days for mosquito eggs to hatch. By getting rid of standing water once a week, or by making water move and flow, mosquito breeding is interrupted and they do not live to spread diseases. To prevent mosquitoes from breeding:
- Get rid of places where water collects (standing water) such as old car tires, flower pots, oil drums, ditches, uncovered water storage containers, and any standing water inside the house.
- Manage land in ways that prevent water from collecting so the water will instead soak into the ground.
- Make sure watersheds are protected so that water will keep flowing.
Remove mosquito breeding sites around the house and community:
Other methods used in community mosquito control programs include:
- Breeding fish that eat mosquitoes. The Central American mosquito fish, South American guppies, African tilapia, carp, and other fish can be used to control mosquitoes. These fish have different common names in different places, but are often called “mosquito fish.”
- Make sure water flows and fields drain by restoring natural waterways, making drainage channels to let water move, and filling in unused irrigation trenches and ponds. Drain rice paddies once a week for 2 or 3 days to kill young mosquitoes without harming rice production.
- Plant trees to provide homes for birds, bats, and other natural helpers in mosquito control. Neem trees from Africa and India keep mosquitoes away and the leaves can be used as medicine.
Where mosquitoes breed only part of the year, they can be quickly destroyed with insecticides. In the past, the pesticide DDT was widely used to kill malaria mosquitoes, and was sprayed outdoors over mosquito breeding sites. But DDT is a poison that does great harm to people and animals, causing cancer and birth defects. DDT can travel great distances in the air and in water, and stays in the environment for many years, becoming more dangerous over time. Because of this, community prevention activities and less toxic insecticides are now recommended in most countries.
One type of insecticide, called pyrethrins, causes less long-term harm to people, animals, and the land. Another advantage of pyrethrins over DDT or malathion (another common but harmful pesticide) is that much less is needed to spray the same amount of space.
Pyrethrins do not collect in the environment. But they are toxic when people are exposed to them, and must be used with care. Pyrethrins irritate the skin and eyes, and cause rashes and difficulty breathing. Avoid direct contact with this insecticide, especially children and women who are pregnant or breastfeeding. Pyrethrins are very toxic if they get into water sources. Never use pyrethrin products near waterways or ponds.
|Insecticides are a short-term
mosquito control measure.
If you must use them, wear
Recently, DDT has come back into use in different ways than before. It is now recommended only for limited use indoors, in a method called Indoor Residual Spraying (IRS). This is spraying small amounts of DDT on the inside walls of a house to kill mosquitoes that land there. This method uses less poison in a smaller area, prevents it from entering water sources, and has less chance of causing mosquitoes to become resistant.
All insecticides are poisons. When using DDT, pyrethrins, or any other insecticide:
- Follow directions and spray with caution.
- Always wear protective equipment when spraying.
- Use as little of the chemical as possible. Spray only where mosquitoes enter the home, and where they live or rest.
- Never spray near children or women who are pregnant or breastfeeding.
- Make sure children do not suck or chew on insecticide-treated bednets, and that they touch the net as little as possible.
- When washing insecticide-treated bednets, use a basin and pour the wash water into a soakaway pit to protect waterways and drinking water sources.
Overuse of any insecticide can cause mosquitoes to become resistant to it and the insecticide will no longer harm them. (To learn more about the dangers of insecticides and how to use them as safely as possible, see Chapter 14.)
Spraying insecticides is an emergency measure for quick mosquito control. But insecticides will only reduce mosquito-borne illnesses if they are used as part of a program that includes treatment for everyone, communitywide control of mosquito breeding, and community education.
Stopping dengue by stopping mosquitoes
Over the past 25 years, people in Managua, Nicaragua have been increasingly getting sick with dengue fever. Because the mosquito that spreads dengue lives in water in and around homes, dengue spreads widely when more people move into tropical cities without safe water storage and wastewater drainage.
People in Managua worked with scientists, NGOs, and the Ministry of Health to reduce and prevent dengue in 10 neighborhoods. The first thing they did was to collect ‘evidence’ of the spread of dengue. Children collected samples of water with mosquitoes in different stages of growth, scientists tested children’s saliva to see how many had been bitten by dengue-infected mosquitoes, and community members visited people’s homes to ask them what they knew and thought about dengue.
They used neighborhood meetings, posters, and sociodramas to share what they learned about dengue. Children played games where they smashed hollow dengue mosquito puppets, scattering the candy hidden inside. Young people, including gang members, wrote and performed popular-style songs about preventing dengue.
Each neighborhood developed its own mosquito control program. Because they knew that mosquitoes breed in discarded tires, one group decided to collect old tires, fill them with soil, and use them to make stairways up steep paths. That got rid of mosquito breeding sites and made it easier to get up and down the hillside. Other tires were used as planters.
A group in another neighborhood made and sold low-cost lids for water storage barrels. This got rid of mosquito breeding sites while also earning money for their community.
The community dengue prevention program continues today. Not only are fewer people getting sick with dengue, but the program has brought other benefits:
- Young people, including gang members, were involved in making positive changes in their neighborhoods, which increased the community’s togetherness.
- Musicians wrote popular songs to educate people, making dengue prevention fun.
- Different religious and political groups put aside their differences to work together on a common project.
- Local health activists were asked to serve on Ministry of Health governing boards for health posts and centers.
Now, people from these 10 neighborhoods are helping other communities get organized to stop dengue and improve community life.