Broward County Health Department: To promote and protect the health and safety of all persons in Broward County through the delivery of quality public health services
Health Topics
The Facts on St. Louis Encephalitis (SLE)

What is SLE?

Arboviral (insect-borne) infections are caused by any of a number of viruses transmitted by insects such as mosquitoes and ticks. These infections generally occur during warm weather months when mosquitoes are active.

Who gets SLE infections?

Anyone can get an arboviral infection, but young children and the elderly appear to be most susceptible.

How is the disease spread?

Most arboviral infections are spread by infected mosquitoes. Fortunately, only a few types of mosquitoes are capable of transmitting the disease and only a small number of the mosquitoes are actually carrying the virus. Occasionally, migrating birds have the ability to carry viruses from one area of the country to another.

To Prevent Infection: Eliminate standing water, Use mosquito repellant, Cover up by wearing long sleeved shirts and long pants.

What are the symptoms of SLE?

Symptoms of the various types of viral infections transmitted by mosquitoes are usually similar, but differ in severity. Most infections do not result in any symptoms. Mild cases may occur with only a slight fever and/or headache. Severe infections are marked by headache, high fever, disorientation, coma, tremors, convulsions, paralysis or death.

When do symptoms appear?

Symptoms usually occur 5 to 15 days after exposure to infected mosquitoes.

Does past infection with arbovirus make a person immune?

Yes, infection with an arbovirus can provide immunity to that specific virus and perhaps to other related viruses.

What is the treatment for an infection due to arbovirus?

The physician will usually attempt to relieve the symptoms of the illness; however, there is no specific treatment or vaccine available for arbovirus infections.

How can SLE be prevented?

Insect repellents can be used when outdoors in mosquito-infected areas. Homes can be screened to prevent entry of mosquitoes. Communities or municipalities may establish a mosquito surveillance or control program to reduce mosquito populations by applying pesticides and draining swampy areas.

Wearing long sleeve shirts and long pants, and restricting outside activities during peak mosquito activity periods (dusk and dawn), can minimize exposure to mosquitoes.

For further information, contact the Broward County Health Department at 954 467-4806.