Each year when the weather warms up, Pueblo County brims with opportunities to spend time in the great outdoors.
But while Puebloans are making the most of the warm weather and spending time outside, another kind of opportunist is preparing for its annual feast: mosquitoes.
Mosquito season in Colorado lasts throughout the warm months of the year but tends to spike in the spring and again in the late summer months.
Here’s what you need to know about the blood-sucking insects — including how to avoid them — in Pueblo County.
Where do mosquitoes like to grow?
Mosquitoes need to grow in stagnant water. Mosquito eggs, also known as larvae, can start growing in just a few inches of water, said Chuck Rodosevich, the regional manager of Vector Disease Control International.
“They hate fresh water; they like nasty, ugly stuff,” Rodosevich said.
Mosquitoes aren’t fans of direct sunlight, Rodosevich said. In ponds, they tend to lay larvae in mucky areas rife with debris, but fish and some other bugs will eat the eggs.
Mosquitoes tend to be more active around dawn and dusk and are attracted to dark colors. They're also attracted to the carbon dioxide humans let out with every breath.
How to avoid or get rid of mosquitoes
To mitigate mosquitos, make sure there aren’t any places where the newly-laid insects can grow. And drain any standing water that can accumulate in places such as extra tires, planter pots or gutters, Rodosevich advised.
Wearing insect repellent with DEET is also key to mitigate mosquitos: a concentration of at least 20%-25% DEET is important for the repellent to be effective.
Rodosevich’s company contracts with the city and county of Pueblo to monitor mosquitoes and mitigate them in public areas but does not work on individual residential properties.
He said that his company uses a pesticide that only targets mosquitoes, which disrupts the growing cycle of their larvae. Other insects and living creatures are not affected by the chemical they use.
People who want their property to be sprayed can buy pesticides or employ other companies.
Why mosquitoes are worse this year
More mosquitoes are in the Pueblo area this year because of increased rainfall and moisture, Rodosevich said.
One certain species of mosquito can lay eggs that remain dormant for years until there’s more moisture around, and floodwater mosquitoes have been hatching more this year, causing an uptick in the mosquito population.
“I'm seeing mosquitoes where I typically don't see mosquitoes,” Rodosevich said.
Floodwater mosquitoes can fly up to 10 miles away from where they hatched in their short lifespan.
Female mosquitoes are the ones who suck blood, which is necessary for their egg production. They usually have a four-week lifespan, while male mosquitoes live for approximately 10 days.
Do mosquitoes help the environment?
Unlike the flocks of miller months — which are pollinators and are harmless to humans — to which Coloradans are accustomed, mosquitoes don’t serve an ecological benefit.
The Centers for Disease Control and Prevention calls mosquitoes the “world’s deadliest animal” because of the effect of mosquito-borne diseases, which kill hundreds of thousands of people every year.
West Nile virus in Pueblo
Rodosevich said that there are over 60 species of mosquitoes that have been detected in Pueblo County, but there’s one that spreads the West Nile virus: Culex mosquitoes.
His company helps monitor the spread of the virus.
What are the chances of getting West Nile virus if bitten by an infected mosquito?
Not great because only a small percentage of mosquitoes carry the virus.
Only 20% of people bitten by infectious mosquitoes will develop mild symptoms of fever, headache and body aches and occasionally a skin rash on the trunk of the body and swollen lymph glands.
About one in 150 people will develop severe or life-threatening symptoms, including high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.
Less than 1% of cases result in death.
During a 2003 West Nile epidemic in Pueblo County, 183 infections and six deaths were reported. Since then, a mass outbreak has not occurred locally: two cases were reported in 2021 and no cases in 2022, according to data from the Colorado Department of Public Health and Environment.
While Pueblo has not recorded many cases of West Nile virus in recent years, Colorado recorded the highest number of cases in 2022 in any U.S. state.
Culex mosquitoes tend to peak in the later months of the summer, Rodosevich said.
Colorado’s environment is too cold and dry for many of the mosquito types that spread diseases such as malaria and yellow fever.
Reporting from our partners at the Fort Collins Coloradoan contributed to this report.
Anna Lynn Winfrey is a reporter at the Pueblo Chieftain. She can be reached at awinfrey@gannett.com or on Twitter, @annalynnfrey.
