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Mosquitoes in 3 Colorado cities test positive for West Nile virus

Mosquitoes in Erie, Louisville, and Longmont have tested positive for West Nile virus.

BOULDER COUNTY — Mosquitoes in three Colorado cities have tested positive for West Nile virus, according to a release from Boulder County Public Health.

The mosquito pools that tested positive came from traps near West Canyon Creek in Erie, Coal Creek Golf Course in Louisville and Jim Hamm Pond in Longmont, the release said.

Right now, the vector index – used to measure the relative risk of contracting the virus – is still pretty low with Erie and Louisville measuring a 0.13 risk and Longmont measuring a 0.11 risk.

Emergency spraying is generally recommended when the vector index is 0.75 or higher, health officials said. The index is calculated by measuring the total number of mosquitoes in a trap compared with the proportion infected with WNV.

Earlier this month, mosquito traps in Fort Collins, Weld County and the Town of Berthoud tested positive for the virus.

WNV is transmitted to humans by infected mosquitoes. As always, health officials urge residents in the area to follow these steps:

  • DRAIN: Mosquitoes breed in water. Drain any standing water in your yard each week. Bird baths, clogged gutters and kiddie pools are common breeding sites.
  • DRESS: Wear lightweight, long-sleeved shirts and long pants while outdoors. Spray clothing with insect repellent since mosquitoes may bite through clothing.
  • DEFEND: Apply insect repellent sparingly to exposed skin. Use an approved repellent according to its label. Click here to find the repellent that is right for you
  • DAWN/DUSK: Limit time spent outdoors at dawn through dusk, when mosquitoes are most active and feeding.

Mosquito season typically lasts from late April until mid-October. Last year, nine people in Boulder County tested positive for the virus.

To learn more about ways to protect yourself, click or tap here.