LaCrosse Encephalitis - Fact Sheet

In Ohio LaCrosse Encephalitis (LAC) is caused by the Aedes trisariatus or "tree hole" mosquito, which breeds in containers and tree holes which hold water for a week or more. These mosquitoes do not breed in puddles, ponds, or ditches. Approximately 20 - 30 LAC encephalitis cases are identified each year in Ohio.

Most cases of LAC encephalitis occur in children under 16 years of age. LAC Encephalitis causes an inflammation of the brain. Symptoms include:

• Headache
• Fever
• Stiff Neck
• Drowsiness
• Lethargy (tiredness, exhaustion)
• Nausea, Vomiting
• Disorientation
• Mental Confusion
• Sometimes - Seizures

Symptoms usually appear 5 to 15 days following infection by a mosquito carrying the virus. The disease causes serious illness in some, requiring hospitalization, however most recover completely. There have been 7 deaths due to LAC Encephalitis in Ohio since 1963. There is no treatment for LAC Encephalitis.

 The Licking County Health Department recommends the following to eliminate mosquito-breeding sites around homes:

• All containers, including buckets, cans, birdbaths, tires, wading pools, and tarps, that may hold water should be emptied once a week during the summer months.
• Proper disposal of scrap tires and other refuse.
• Clean downspouts to permit proper drainage.

The Health Department also recommends the following to reduce exposure when mosquitoes are present:

• Wear light-colored clothing including long sleeved shirts, and slacks.
• Repair door and window screens on homes.
• Use an insect repellent with no more than 30% active ingredient, applied to clothing and exposed skin, following the directions on repellent label.
• Limit outdoor activities at dawn and dusk, when mosquitoes are most active.

 Sources of additional info:

http://www.cdc.gov/ncidod/dvbid/arbor/index.htm

http://www.odh.state.oh.us/resources/facts/lacross.htm