October 1, 2001

Houston Department of Health and Human Services (HDHHS) officials confirmed the city’s first case of Saint Louis encephalitis (SLE) since 1998. A second strongly suspect case is under investigation.

The confirmed case, a 54-year-old male, experienced onset of SLE in late August. Following hospitalization, the patient is recovering. It is believed that the exposure occurred at or near his place of employment near downtown. No infected mosquito pools had previously been identified in this area. Harris County Mosquito Control (HCMC) conducted spraying operations in the area immediately after the suspected case had been reported.

The second suspect case resides east of downtown Houston, an area previously identified by HCMC as having pools of infected culex mosquitoes. The 54-year-old female also experienced onset in late August and was hospitalized. She is recovering at home. HCMC continued spraying in the neighborhood.

SLE is transmitted to humans through the bite of an infected culex mosquito. The symptoms of SLE include headache, high fever, muscle aches, chills, stiff neck, lethargy or fatigue and change of mental status. Symptoms generally begin five to 10 days after being bitten by an infected culex mosquito. Most people bitten by an infected culex mosquito will never experience any symptoms. The elderly are at highest risk for developing serious disease after exposure.

To reduce your risk of exposure to mosquito bites, including infected culex mosquitoes, remove all pools of standing water near your home: bird baths, tires, flower pot pans, magnolia leaves, etc. Standing water as small as a bottle cap is sufficient for mosquito breeding. Ensure that window screens are secure and that mosquitoes do not enter the home through cracks or excessive door/window opening. When outside, wear long sleeved shirts and long pants. Use an insect repellent, which contains the active ingredient Deet, following label instructions.