West Nile virus
The risk for mosquito-born infections is highest between dusk and dawn, when mosquitoes feed. A good insect repellent is very helpful in reducing the risk for vector-borne disease. The most complete personal protection program for adults and most children is to apply the insect repellant DEET to the skin, and also permethrin to clothing and other surfaces.
DEET. Most insect repellents contain the chemical DEET (N,N-diethyl-meta-toluamide), which remains the gold standard of currently available mosquito and tick repellents. DEET has been used for more than 40 years and is safe for most children when used as directed. Comparison studies suggest that DEET preparations are the most effective insect repellents now available.
Concentrations range from 4% to almost 100%. The concentration determines the duration of protection. Most adults and children over 12 years old should use preparations containing a DEET concentration of 20 - 35% (such as Ultrathon), which provides complete protection for an average of 5 hours. (Higher DEET concentrations may be necessary for adults who are in high-risk regions for prolonged periods.)
Never use DEET products should on infants younger than 2 months. According to the Environmental Protection Agency (EPA), DEET products can safely be used on all children age 2 months and older. The EPA recommends that parents check insect repellant product labels for age restrictions. If there is no age restriction listed, the product is safe for any age. The American Academy of Pediatrics recommends that children use concentrations of 10% or less; 30% DEET is the maximum concentration that should be used for children. When deciding what concentration is most appropriate, parents should consider the amount of time that children will be spending outside, and the risk of mosquito bites and mosquito-borne disease.
When applying DEET, take the following precautions:
Other Insect Repellent Products. The U.S. Centers for Disease Control (CDC) also recommends the mosquito repellents picaridin and oil of lemon eucalyptus.
Picaridin, also known as KBR 3023 or Bayrepel, is an ingredient that has been used for many years in repellents sold in Europe, Latin America, and Asia. A product containing 7% picaridin is now available in the United States. Picaridin can safely be applied to young children and is also safe for women who are pregnant or breast-feeding. According to the CDC, insect repellents containing DEET or picaridin work better than other products.
In scientific tests, oil of lemon eucalyptus, also known as PMD, worked as well as low concentrations of DEET. However, oil of lemon eucalyptus is not recommended for children under the age of 3 years.
Permethrin is an insect repellent used as a spray for clothing and bed nets, which can repel insects for weeks when applied correctly. Electric vaporizing mats containing permethrin may be very helpful. A permethrin solution is also available for soaking items, but it should never be applied to the skin. Side effects from direct exposure may include mild burning, stinging, itching, and rash. In general, however, permethrin is very safe and its use may even reduce child mortality rates from malaria. People allergic to chrysanthemum flowers or who are allergic to head-lice scabicides should avoid using permethrin.
Eliminate Sources of Standing Water. Currently, the only proven method for reducing mosquito populations is to eliminate sources of standing water.
Mosquito Traps. Mosquito traps use various methods for repelling or attracting and trapping the insects. Effective traps are expensive, and they usually require electricity or propane, which adds to the cost. Use mosquito trap machines only outdoors. While many traps can draw in significant numbers of mosquitoes, they have limitations. Do not rely on them for sole protection.
All baits should aim to attract the female mosquito, which is the primary transmitter of the viruses. However, different baits may be more or less effective. Some may even attract one species and not others.
Bug Zappers. Insect light traps (commonly called bug zappers), which attract and electrocute insects, may actually spread viruses and bacteria that are on the insects. They are also not very effective for killing female mosquitoes.
Encouraging Natural Defenders. Some attempts have been made to control mosquito populations with natural defenders, including building bat and bird houses to attract natural predators or growing certain insect-repellent plants.
Citronella Candles. Burning citronella candles reduces the likelihood of bites. (Indeed, burning any candle helps to some extent, perhaps because the generation of carbon dioxide diverts mosquitoes toward the flame.)
Your home environment, personal hygiene, and what you wear can also help reduce your risk for mosquito bites:
Public health measures are the best methods for controlling mosquitoes.
Spraying. Local areas that experience outbreaks of encephalitis from mosquitoes usually have a spraying program.
Report Dead Birds. Dead birds may be indicators that the West Nile virus has reached a specific region. Report any dead birds to your local public health authorities. You should never touch a dead bird with your bare hands.
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