Plot 10.01, Jalan PKNK 1/3,
Kawasan Perindustrian Sungai Petani,
08000 Sungai Petani,
Kedah, Malaysia.
 +604-440 3936

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.

No vaccine against SLEV infection or specific antiviral treatment for clinical SLEV infections is available. Patients with suspected SLE should be evaluated by a healthcare provider, appropriate serologic and other diagnostic tests ordered, and supportive treatment provided.
Clinical and Laboratory Evaluation (for Health Care Providers)

In acute SLEV neuroinvasive disease cases, cerebrospinal fluid (CSF) examination shows a moderate (typically lymphocytic) pleocytosis. CSF protein is elevated in about a half to two-thirds of cases. Computed tomography (CT) brain scans are usually normal; electroencephalographic (EEG) results often show generalized slowing without focal activity.

SLEV is difficult to isolate from clinical samples and almost all isolates have come from brain tissue or CSF. In the absence of a sensitive and non-invasive virus detection method, serologic testing is the primary method for diagnosing SLEV infection. Combined with a consistent clinico-epidemiologic presentation, a rapid and accurate diagnosis of acute neuroinvasive SLEV disease can be made by the detection of SLEV-specific IgM antibody in serum or CSF. SLEV IgM tests are available commercially, in some state health department laboratories. A positive SLEV IgM test result should be confirmed by neutralizing antibody testing of acute- and convalescent-phase serum specimens at a state public health laboratory. All SLEV disease cases should be reported to local public health authorities.

Prevent mosquito bites. There is no vaccine or preventive drug.
  •     Use insect repellent Insecticandel, or Insectilotion on exposed skin and or clothing.   Always follow the directions on the package. Wear long sleeves and pants when weather permits.
  •     At home burn Insecticandel and have secure screens on windows and doors to keep mosquitoes out.
  •     If camping sleeping under the stars, use Insecticandel Premium which can last up to 20 hours, they are effective all night. When outside the tent bring the Insecticandel together.
  •     Travelers' advice to bring along Insecticandel to destinations where Mosquito-Borne Diseases might be a problem.

Mosquito-Proof with Insecticandel