It's the beginning of summer and the beginning of mosquito season.
While no reported cases of the West Nile virus have surfaced in Missouri this year, Boone County health officials said they're still preparing.
"It's still a concern because we have several low lying areas that tend to collect water, near lakes, rivers and trails," said Andrea Waner with Public Health Services.
Waner said it's hard to forecast if mosquitoes will pose a health threat, and if so, how large.
"[It's] predictably unpredictable," she said. "It's similar to flu season in that regard, that you know the mosquitoes are coming, you know because of where we live, that it's hot, it's humid and muggy. You know it's inevitable, but how severe it's going to be, that's pretty much unpredictable."
In Boone County, the first spray will begin on Friday at midnight and target the MKT trail and parks.
Some residents in the area who spend a lot of time outside are thrilled.
"As an endurance runner, usually I do a lot of my runs in the evening because of the cooler temperatures," said Nick Hayden, who uses the MKT trail regularly. "I run on the trail and by the time I'm done with my run, I'm just covered in mosquitoes all over. It's almost like a blanket."
While mosquitoes are nothing new, the concern for West Nile has grown over the years.
In 2013, there were 29 cases of West Nile reported in Missouri. Four of those cases were in mid-Missouri counties.
Health officials said neighborhoods are not sprayed unless there is a West Nile virus case reported.
They also said wearing mosquito repellant is a recommended precaution.
In Cole County, health officials said they've already started spraying for mosquitoes and will continue throughout the season.