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Public Health - Seattle & King County

Protecting yourself and your family from mosquitoes

Fight the Bite

3 steps to prevent mosquito bites

We will never be able to eliminate all mosquitoes, but you can take personal precautions to avoid being bitten. Stay inside or take extra care at dawn and dusk when mosquitoes are most active. To avoid mosquito bites while outdoors:

  • Wear long sleeve shirts, long pants, socks and a hat
  • Wear light-colored clothing (mosquitoes are attracted to dark colors)
  • Use an insect repellent
Insect repellents

Repellents for use directly on skin

The Centers for Disease Control and Prevention (CDC) recommends the use of insect repellents that include active ingredients which have been registered by the U.S. Environmental Protection Agency (EPA). The following active ingredients have been reviewed and approved by the EPA for effectiveness and human safety if applied according to the instructions on the product label.

  • DEET (Chemical Name: N,N-diethyl-meta-toluamide or N,N-diethyl-3-methyl-benzamide)

  • Picaridin or KBR 3023 (Chemical Name: 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester)

  • Oil of Lemon Eucalyptus or PMD, the synthesized version of lemon eucalyptus (Chemical Name: para-Menthane-3,8-dial)

  • IR3535 (Chemical Name: 3-[N-Butyl-N-acetyl}-aminopropionic acid, ethyl ester)

The EPA characterizes DEET and picaridin as “conventional repellents” and Oil of Lemon Eucalyptus, PMD and IR3535 as “biopesticide” repellents, which are derived from natural materials.

Female mosquitoes bite because they need the protein found in blood to develop their eggs. Mosquitoes are attracted to people by skin odors and carbon dioxide from breath. Insect repellents do not kill the mosquitoes but repel or keep away insects. Repellents are effective only at short distances from the treated surface, so you may still see mosquitoes nearby.

Always read the label carefully for any warnings as well as to determine the active ingredient and its concentration. The effectiveness and duration of protection of different products varies and is affected by temperature, amount of perspiration, water exposure, and other factors. Products with higher concentrations of the active ingredient usually provide protection for longer periods of time, although there is no increased benefit of using products with 50% or higher concentration. Products with less than 10% concentration may offer only limited protection, generally for 1-2 hours. Some products have sustained or controlled release (micro-encapsulated) formulations, which may provide longer protection times, even at lower concentrations. Follow label directions and reapply repellent if you start to get mosquito bites. See below for additional guidance.

Selecting the appropriate insect repellent for children:

  • 1 - 2 hours
    < 10% DEET
    < 10% picaridin

  • 2 - 4 hours:
    ~15% DEET
    ~15% picaridin
    ~30% oil of lemon eucalyptus

  • 5 - 8 hours
    ~20%-30% DEET

Adapted from the Centers for Disease Control and Prevention's "How do I choose an Insect Repellent?"

Repellents for use on clothing

Products containing permethrin can be used on clothing, shoes, bed nets, and camping gear and are registered by the EPA for this use. Permethrin on clothing both kills insects and acts as a repellent. Permethrin products should NOT be used directly on the skin. Read the label and follow instructions when applying. Treated clothing provides protection for up to 2 weeks and can be machine washed several times before losing effectiveness. Pre-treated clothing is also commercially available at outdoor and sporting goods stores. In addition to repelling mosquitoes, permethrin-treated clothing also repels and kills ticks.

Precautions when using repellents
  • Always follow product label instructions.
  • Use only enough repellent to cover exposed areas of skin; reapply if mosquitoes start biting.
  • Do not apply repellent to areas that are covered by clothing.
  • Never use repellents over cuts or irritated skin, and do not spray into eyes or mouth.
  • Do not apply directly to face, but spray on hands first and then apply to face.
  • Wash off treated areas of skin with soap and water after returning indoors.
  • Wash treated clothing before wearing again (this may vary by product, follow label instructions).
  • If you get a rash or another reaction, stop using the repellent and wash off the treated area with mild soap and water, and call the Washington Poison Center at 1-800-222-1222. If you see a health care provider, bring the product with you.
  • The Centers for Disease Control and Prevention (CDC) recommends against use of single combination products containing DEET and sunscreen because the instructions for insect repellent and sunscreen use are different (sunscreen usually needs to be applied more often than insect repellent). Instead use separate insect repellent and sunscreen products. Apply sunscreen first, then repellent.
  • See Protecting your children from West Nile Virus for information about use of insect repellents for children.
Resources
Report dead birds
Report dead birds

Help us fight West Nile virus! If you see a dead bird in King County, report it through the Washington State Dept. of Health's online dead bird reporting website.

See photo-illustrated Bird Identification Gallery for names of birds.