Medical expert of the article
New publications
Encephalitis St. Louis (American): causes, symptoms, diagnosis, treatment
Last reviewed: 07.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
St. Louis encephalitis (American) is common in various parts of the United States. The causative agent of the disease is an arbovirus (filterable neurotropic virus) transmitted by blood-sucking mosquitoes. The disease occurs in late summer in small epidemics.
Symptoms of American Encephalitis St. Louis
The onset of the disease is acute, with a rise in body temperature to 38-39 °C, herpetic eruptions on the skin and mucous membranes. Headache, disturbances of consciousness of varying severity are noted. Meningeal syndrome is revealed. Development of focal neurological symptoms in the form of hemi- or monoparesis, cerebellar disorders is possible. Lymphocytic pleocytosis (from 50 to 500 cells in 1 μl) and some increase in protein content are usually found in the cerebrospinal fluid. Moderate polymorphic cellular leukocytosis is found in the blood.
The course is favorable. Clinical forms are varied. Often the disease is abortive, passes quickly and without a trace.
The diagnosis is confirmed by neutralization and complement fixation reactions.
[ Where does it hurt?
What do need to examine?
What tests are needed?