Officials said that residents shouldn't be alarmed, but this is a reminder to take precautions when outdoors.

ST. CHARLES COUNTY, Mo. — A sample of mosquitoes in St. Charles County tested positive for the West Nile virus during routine testing, The county's public health department announced on Friday.

It's not a cause for alarm, officials said, but it is a reminder to continue taking precautions when outside to avoid mosquito bites.

This is the first positive result staff has had in the county this year as part of the Division of Environmental Health and Protection's Mosquito Control Program. They've done more mosquito trapping and testing than usual because the rain the area has seen this summer has increased the insect's breeding grounds.

The health department lists its recommendations for how to control mosquitoes on its website, including wearing repellant and removing standing water from homes and yards.

West Nile virus usually presents in humans with symptoms of fever, headache, body ache, vomiting and rash.