Stage 1 fire restrictions, enacted for unincorporated areas of western Boulder County.

Personal West Nile Virus Prevention
woman spraying son for mosquitoes

Personal West Nile Virus Prevention

En español

The only treatment available for West Nile virus (WNV) is prevention.

Personal Prevention – the Four Ds

Because WNV can cause such a debilitating illness in 20% of those infected, and no treatment is currently available, everyone should take precautions to prevent being bitten by mosquitoes.

Follow the Four D’s when mosquitoes are most active (June through September) to help reduce the risk of being infected with WNV.

Use insect repellant that contains at least 10% DEET. If outside during evening, nighttime, and dawn hours, consider the use of an insect repellant containing 10% to 30% DEET (N, N-diethyl- methyl-meta-toluamide). Products with concentrations around 10% are effective for periods of approximately two hours.

Use DEET according to manufacturer’s directions:

  • DEET is not recommended for children under 2 months of age.
  • Do not apply DEET directly to children, and do not apply it to children’s hands. Apply to your own hands, then put it on the child.
  • Apply DEET sparingly on exposed skin; do not apply under clothing.
  • Do not use DEET over cuts, wounds, or irritated skin. Wash all treated skin and clothing after returning indoors.

Dress in long sleeves and long pants. If outside during evening, nighttime, and dawn hours when mosquitoes are most active and likely to bite, children and adults should wear protective clothing such as long pants, long-sleeved shirts, and socks.

Reduce or eliminate outdoor activity between dusk and dawn.

Make sure windows are closed or screened.

Most mosquito species are actively searching for a blood meal in the evening hours from just before dark until 2 to 3 hours after dark. During the daytime the females normally rest in cooler vegetated areas where the humidity is higher and they are protected from drying out. Females will often bite in the daytime if humans or animals invade the wooded areas where they are resting.

Make sure to drain standing water around your home.

  • Remove all discarded tires from your property.
  • Dispose of tin cans, plastic containers, ceramic pots, or similar water-holding containers.
  • Make sure roof gutters drain properly. Clean clogged gutters in the spring and fall.
  • Clean and chlorinate swimming pools, outdoor saunas, and hot tubs. If not in use, keep empty and covered.
  • Drain water from pool covers.
  • Change the water in bird baths at least once a week.
  • Turn over plastic wading pools and wheelbarrows when not in use.
  • Eliminate any standing water that collects on your property.
  • Remind or help neighbors to eliminate breeding sites on their properties.

Learn more about preventing mosquitoes on your property.

Contact Us

Vector Control Program

Main: 303-441-1564
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