Colorado's wet June was a relief for drought conditions, but all that moisture and recent hot weather has created ideal breeding grounds for mosquitoes. One species — the Culex mosquito — transmits West Nile virus.
"This time last year in the town of Berthod we would see about 50 to 100 just pure Culex numbers — the number of mosquitoes. Last week we saw over 5,000," said Larimer County Public Health Director Tom Gonzales.
Fort Collins, Loveland, Timnath and other Front Range communities are seeing similar numbers. Larimer County has more than 100 traps set up to capture mosquitoes. They work with a contractor to count species from the traps and then test pools of the mosquitoes for the virus at Colorado State University. When all is said and done, a "vector index" is used to gauge the potential risk of the virus.
With the Culex population so high, Gonzales said it's likely there will be more human cases of West Nile this summer.
"We are strongly encouraging and recommending anybody dusk to dawn cover your body as much as possible, use a mosquito repellent," he said.
Getting rid of any standing water around your house or in your yard will also help cut down risk. But Gonzales said the problem is bad enough that cities and towns are starting to spray.
"Nobody wants to spray, but with this risk we have to weigh out that and right now it's important to knock the amount of adult mosquitos down that we're just seeing to get to more to a routine year where we're seeing 100 to 200 Culex mosquitos not thousands," he said.
Fort Collins will start spraying this Sunday. You can see a map of the area being sprayed and track the fogging trucks online. Other spray schedules in Larimer County can be found here. Residents should stay indoors and keep windows closed for 30 to 60 minutes after spraying occurs.
West Nile first appeared in Northern Colorado in 2003. About 1 in 150 people infected with the virus will develop severe illness.