West Nile Virus
Denver traps and collects adult mosquitoes at five sites across the city to determine if West Nile Virus (WNV) is present in local mosquito populations. The samples are sent for testing to the Colorado Department of Public Health and Environment.
Testing of adult mosquitoes over the past several years documented the occurrence of WNV in Denver’s adult mosquito populations in 2007, 2011 and 2014. Testing of Denver’s adult mosquitoes did not occur in 2012 and 2013.
Data for neighboring counties indicates that WNV was found in adult mosquitoes throughout the region in 2014, particularly rural areas north of Denver along the front range.
The number of Culex species (those most likely to carry WNV) collected in Denver traps is comparable to, or lower than, what was found in nearby counties (Adams, Arapahoe, Boulder, Jefferson).
What does this mean for you?
While the risk of exposure to WNV is low, you should still protect yourself. Mosquitoes generally remain active throughout the summer until September or until colder nights set in (e.g. 40’s). See “Protect Yourself from Mosquito Bites” for more information.
Zika Virus is most commonly spread to people through mosquito bites. The mosquito that spreads Zika lives mostly in warm (tropical and subtropical) regions of the world and is not found in Colorado. The risk of Zika coming to Colorado and spreading through mosquito bites is very low.
DDPHE and Denver Public Health are working closely to monitor the spread of the disease, identify risks and plan for the possibility of a case in the metro area.
View a Zika Virus fact sheet in English and Spanish.