Saint Louis encephalitis

Saint Louis encephalitis (SLE) is a disease caused by the Saint Louis encephalitis virus (SLEV), a member of the Flavivirus family. It is named after the city of Saint Louis, Missouri, where the virus was first identified in 1933. The disease is primarily spread through the bite of an infected mosquito, and is found throughout the United States, particularly in the Midwest and South.

Epidemiology

SLE is most common in rural and suburban areas, particularly in regions with high mosquito populations. The disease is most prevalent during the summer and early fall, when mosquitoes are most active. The Centers for Disease Control and Prevention (CDC) estimates that there are between 63 and 187 cases of SLE in the United States each year.

Symptoms

Most people infected with SLEV have no apparent illness. Initial symptoms of those who become ill include fever, headache, nausea, vomiting, and tiredness. Severe neuroinvasive disease (often involving encephalitis, an inflammation of the brain) occurs more commonly in older adults. In rare cases, long-term disability or death can result.

Diagnosis

Diagnosis is based on tests of blood or cerebrospinal fluid (CSF). The tests detect antibodies that the immune system makes against the viral infection.

Treatment

There is no specific treatment for SLE. Care is based on symptoms. In severe cases, hospitalization, respiratory support, and intravenous fluids may be required.

Prevention

Prevention centers on controlling mosquito populations and preventing mosquito bites. This includes the use of insect repellent and wearing protective clothing.

See also

• West Nile virus
• Japanese encephalitis
• Eastern equine encephalitis virus
• Western equine encephalitis virus