HEALTH
Rare, serious mosquito spread illness found in Upstate South Carolina
Joyce OrlandoUSA TODAY NETWORK
Aug. 3, 2026, 6:45 a.m. ET
A person in South Carolina has been infected with a rare and serious viral illness after being bitten by a mosquito
Oconee County Emergency Services posted on Facebook on Thursday, July 30, that the South Carolina Department of Public Health confirmed a case of La Crosse encephalitis, otherwise known as LACE, in a county resident. LACE is a rare viral illness that “has been known to be prevalent in the Upstate.”
While not spread person to person, health department officials are urging people to take steps to prevent mosquito bites by using insect repellent containing DEET, picaridin, or oil of lemon eucalyptus when spending time outdoors
Here’s what people should know about the illness and how to prevent mosquito bites
What is LACE, La Crosse encephalitis?
LACE is considered rare, but does show up in South Carolina. The Centers for Disease Control and Prevention report that cases typically occur in states in the upper Midwest, mid-Atlantic, and Southeast
The viral illness is spread to person. LACE is most often reported in children under 16
What are the symptoms of LACE, La Crosse encephalitis?
Many who have contracted this illness never show symptoms, the CDC reports. But people can also exhibit symptoms including:
- Fever
- Headache
- Nausea
- Vomiting
- Fatigue
Some could develop a severe form of LACE, including encephalitis (inflammation of the brain). Symptoms of severe illness include:
- Paralysis
- High fever
- Headache
- Neck stiffness
- Stupor
- Disorientation
- Coma
- Seizures
- Muscle weakness
- Vision loss
- Numbness
Tips to keep mosquitoes away
South Carolina emergency and health officials offer tips to help mitigate the mosquito population and to keep yourself safe
- Eliminate standing water around the home — the mosquitoes that carry LACE breed in small containers, treeholes, old tires, buckets, and clogged gutters, not in ponds or large bodies of water.
- Use insect repellent containing DEET, picaridin, or oil of lemon eucalyptus on children and adults when outdoors.
- Dress protectively — long sleeves and pants during outdoor activity, especially in wooded areas.
- Repair window and door screens to keep mosquitoes out of the home.
- Supervise outdoor activities near wooded or brushy areas where treehole mosquitoes are more active during daylight hours.
