Hesperian Health Guides
Prevent Illness by Stopping Mosquitoes
To do this, you must know where different kinds of mosquitoes like to breed, where they like to rest, and when they bite. For example, malaria mosquitoes are most common in rural areas, and often breed in swamps and other still water. The dengue and yellow fever mosquitoes stay inside or near houses, where clean water collects or is stored, both in rural areas and in cities. In the house, many mosquitoes hide in shady, dark places, such as under tables or beds, or in corners. Outside, they find shady areas.
How mosquitoes spread disease
Avoid mosquito bites
- Wear clothes that cover the arms, legs, feet, neck, and head as much as possible (long sleeves and long pants or skirts, a head covering and closed shoes, or socks with sandals).
- Use wire mesh (screens) on windows, doors, and vents. Fill in any gaps around the windows and repair holes in the screens.
- With no screens, close doors and windows when mosquitoes are out.
- The moving air from a fan can keep mosquitoes away.
- Use bednets at night and if resting during the day.
- Use a net to protect you from mosquitoes when sleeping outdoors.
Bednets help stop mosquito bites
Bednets prevent mosquito illness in 2 ways. A bednet with no holes or openings keeps the mosquito from reaching someone under the net. And a bednet treated with insecticide kills the mosquitoes that land on the net. To lower the number of mosquitoes bringing illness to the community, use one for each bed in every home. Programs give away insecticide-treated bednets because when everyone uses them, mosquitoes are fewer and there is less malaria.
To keep mosquitoes from biting, always tuck the edges of the nets under the bed or sleeping mat so there are no openings. Bednets only work if holes or tears are quickly repaired.
Bednets that come treated with insecticide are meant to be long-lasting, which means that the insecticide can work well for a year or even a few years. If you buy or are given a bednet, find out how long the insecticide is meant to last and if washing the net too much makes it less effective.
With older bednets, the insecticide will eventually wear off. If the bednet is still in good condition, you can mix and apply new insecticide, but if the bednet has many rips or tears it is safer to replace it. When reapplying insecticide to the bednet, wear gloves and pay careful attention to the directions to stop the chemicals from getting on or inside your body.
For any bednet treated with insecticides, do not let children suck or chew on them and do not wash them in a river or water where the insecticide can harm fish, insects, animals, and people downstream.
The malaria mosquito mostly bites at night, making bednets especially helpful in preventing malaria and any other illness caused by the same mosquitoes. The mosquitoes that carry dengue, yellow fever, Zika, and chikungunya bite during the day. For small children or others sleeping or resting during the day, bednets will help prevent these illnesses too. Also, bednets will keep those who are already ill from being bitten by a mosquito that could then give the illness to others.
Repellents and insecticides stop mosquito bites
Repellents are chemicals that mosquitoes do not like, so they stay away. Insecticides are chemicals that kill mosquitoes after they land on an insecticide-treated surface, such as a wall or bednet.
- For your skin, use natural repellents like citronella, neem oil, concentrate from lemongrass or basil leaf. Or use chemical repellents that have one of these ingredients: DEET, Picardin (KBR 3023, icaridin), IR3535, or PMD and other oil of lemon eucalyptus compounds. Repellents can be especially useful protecting children but read the label carefully to make sure the product is safe for children. The label will also say how often to reapply, usually every few hours.
- Where there is Zika, health authorities may provide repellents to women because Zika can harm a woman’s pregnancy.
- Permethrin is a chemical that should not be applied to the skin but can be sprayed on bednets, clothes or shoes to keep mosquitoes away. To keep the chemical off your skin, spray the clothes and let them dry before you put them on. Follow the instructions on the label.
- Only use mosquito coils until you can find a better repellent. The smoke from the mosquito coils and other methods to create smoke to repel mosquitoes can harm your breathing.
Spraying insecticides to kill mosquitoes
Governments or other organizations may carry out programs to kill mosquitoes by spraying insecticides on inside walls at the time of year when there are most mosquitoes. This is called IRS or Indoor Residual Spraying. Anyone applying insecticides needs protection to prevent the insecticides from getting in the body by breathing or by touching the mouth or skin. To stop malaria, this kind of spraying works best when all houses in the same area are sprayed. As with all chemicals including insecticides, keep children from getting the chemicals in their mouths or on their body.