St. Louis Encephalitis

Definition

St. Louis encephalitis is an infection from a mosquito. It can range from mild to life-threatening.

The Central Nervous System

si1210_97870_1_central_nervous
Copyright © Nucleus Medical Media, Inc.

Causes

St. Louis encephalitis is caused by a virus. It is spread to humans from the bite of an infected mosquito. The virus is not spread from person to person.

Risk Factors

Things that may raise the risk of St. Louis encephalitis are:

  • Older age
  • Living in or visiting the southern, central, or western US, especially during summer and fall

Symptoms

St. Louis encephalitis can cause a wide range of symptoms. However, sometimes there are no symptoms. The disease can be mild, severe, or even fatal.

Symptoms may be:

  • Fever
  • Headache or stiff neck
  • Feeling dizzy or lightheaded
  • Nausea
  • Weakness
  • Uncontrolled body movements
  • Loss of control of muscles
  • Confusion, lack of responsiveness, or coma

Diagnosis

The doctor will ask about your symptoms and health history. A physical exam will be done. Blood tests are usually used to diagnose the virus.

Treatment

There is no specific treatment for St. Louis encephalitis. Treatment depends on how severe the disease is. The goal is to manage symptoms and problems. Depending on the symptoms, options may be:

  • Pain medicines—for headaches
  • Anti-nausea medicines
  • Fluids—by mouth or IV
  • Breathing support

Prevention

To reduce the risk of St. Louis encephalitis:

  • Avoid mosquito bites by:
    • Covering up the skin
    • Using bug sprays, netting, and screens
    • Staying inside between dusk and dark

RESOURCES:

Centers for Disease Control and Prevention
https://www.cdc.gov
National Institute of Allergy and Infectious Diseases
https://www.niaid.nih.gov

CANADIAN RESOURCES:

Alberta Ministry of Health
https://www.alberta.ca/health.aspx

References:

Curren EJ, Lindsey NP, et al. St. Louis encephalitis virus disease in the United States, 2003-2017. Am J Trop Med Hyg. 2018;99(4):1074-1079.
Measurement of St. Louis encephalitis virus antibody. EBSCO DynaMed website. Available at: https://www.dynamed.com/lab-monograph/measurement-of-st-louis-encephalitis-virus-antibody. Accessed April 2, 2021.
Mosquito avoidance. EBSCO DynaMed website. Available at: https://www.dynamed.com/prevention/mosquito-avoidance. Accessed April 2, 2021.
Saint Louis encephalitis fact sheet. Centers for Disease Control and Prevention website. Available at:
...(Click grey area to select URL)
Accessed April 2, 2021.
Last reviewed December 2020 by EBSCO Medical Review Board David L. Horn, MD, FACP
Last Updated: 4/2/2021

EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

To send comments or feedback to our Editorial Team regarding the content please email us at healthlibrarysupport@ebsco.com. Our Health Library Support team will respond to your email request within 2 business days.