St. Louis Encephalitis

St Louis encephalitis is a viral infection of the brain, spinal cord or the meningeal lining caused by a member of the flavivirus family called the St. Louis Encephalitis virus. Its presentation can range from no symptoms, to mild headache to severe cases involving confusion, seizures, coma and death.

Where does it occur?

It primarily occurs in Southern Canada, USA, and Northern Mexico.

How is it transmitted?

It is transmitted through the bite of infected mosquitoes.

Is it contagious from person to person?

It is not contagious from person to person.

What is the risk for travelers?

The risk is generally low for travelers.

How soon after exposure will one develop symptoms?

One develops symptoms generally 1-2 weeks after exposure.

What are the signs and symptoms?

Most individuals infected by the virus have no symptoms. Mild cases have symptoms of fever, headache, stiffness of the neck, body aches, nausea and vomiting. Symptoms can progress to severe headache, confusion, disorientation, seizures, coma and paralysis.

Are there any lab tests to diagnose the illness?

Antibody and PCR tests against the virus can be performed on blood or spinal fluid. Rarely, the virus can be cultured from blood or spinal fluid.

Is there any treatment?

There is no specific treatment, measures are entirely supportive with fluids, rest and pain medications etc.

What preventive measures can be taken?

Avoid insect bites by following insect safety measures.

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