St. Louis encephalitis (patient information)
For the WikiDoc page for this topic, click here
|
St. Louis encephalitis |
|
St. Louis encephalitis On the Web |
|---|
|
Risk calculators and risk factors for St. Louis encephalitis |
Overview
Saint Louis encephalitis virus (SLEV) is transmitted to humans by the bite of an infected mosquito. Most cases of SLEV disease have occurred in eastern and central states (see map). Most persons 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. There is no specific treatment for SLEV infection; care is based on symptoms. You can reduce your risk of being infected with SLEV by using insect repellent, wearing protective clothing, and staying indoors while mosquitoes are most active. If you think you or a family member may have SLEV neuroinvasive disease, it is important to consult your healthcare provider for proper diagnosis.
What are the symptoms of St. Louis encephalitis?
Less than 1% of St. Louis encephalitis virus (SLEV) infections are clinically apparent and the vast majority of infections remain undiagnosed. The incubation period for SLEV disease (the time from infected mosquito bite to onset of illness) ranges from 5 to 15 days. Onset of illness is usually abrupt, with fever, headache, dizziness, nausea, and malaise. Signs and symptoms intensify over a period of several days to a week. Some patients spontaneously recover after this period; others develop signs of central nervous system infections, including stiff neck, confusion, disorientation, dizziness, tremors and unsteadiness. Coma can develop in severe cases. The disease is generally milder in children than in older adults. About 40% of children and young adults with SLEV disease develop only fever and headache or aseptic meningitis; almost 90% of elderly persons with SLEV disease develop encephalitis. The overall case-fatality ratio is 5 to 15%. The risk of fatal disease also increases with age.