PUBLIC HEALTH FACT SHEET
What is St. Louis Encephalitis?
St. Louis Encephalitis, or SLE, is a serious viral disease that is transmitted to humans and animals through mosquito bites.
How is St. Louis Encephalitis spread?
The virus that causes SLE lives almost exclusively in the bloodstream of infected birds, and in the mosquitoes that bite those birds. On rare occasions an infected bird will be bitten by a mosquito that bites both birds and people (and other animals), and in that rare situation the virus can “spill over” into a person. The risk of getting SLE, although extremely small, rises during July through September.
What is the treatment for SLE?
There is no specific treatment. Medical care centers on treatment of symptoms and complications.
What can we do to prevent SLE?
The best way to protect yourself is to avoid mosquito bites as much as possible, by:
- Using repellents. Insect repellents containing 20-30% DEET work best. Follow the label instructions carefully. Do not use repellents on children younger than two years of age.
- Limiting outdoor activity in the evening, when mosquitoes are most active.
- Maintaining window and door screens to keep mosquitoes out.
- Reducing mosquito populations; eliminate all standing water that collects in birdbaths, boats, buckets, tires, unused pools, roof gutters, and other containers.
- Avoiding shaded areas where mosquitoes may be resting.
- Wearing protective clothing such as long-sleeved shirts and pants.
SYMPTOMS OF ST. LOUIS ENCEPHALITIS
- Abrupt onset of fever