Tennessee Reports First Case of La Crosse Encephalitis in 2006

Nashville, July 21, 2006 A Middle Tennessee child has been reported as having a severe neurological illness caused by La Crosse Encephalitis virus. La Crosse Encephalitis (LAC) is a mosquito-borne illness that usually infects children 16 years and under. Since 1997, the Tennessee Department of Health has been actively involved in LAC surveillance and reports an average of 15 cases per year. There were 13 cases reported in 2004. Most cases occur in the eastern half of the state.

LAC is a viral illness that can cause a brain infection. Early symptoms may include headache, fever, nausea and vomiting and may progress to more advanced symptoms, including severe headache, stiff neck, muscle aches, drowsiness, disorientation and seizures. LAC can not be spread from person to person. If you notice these symptoms in you or a family member, call your physician or seek medical attention immediately.  

Since prevention is the best defense against mosquito-borne illness, the Tennessee Department of Health offers tips on how to reduce the risk of contracting a mosquito-borne illness. Although mosquito repellents containing DEET have been the mainstay for several years, two additional products are now available: Picaridin and oil of lemon eucalyptus.   

“Most mosquitoes species likely to transmit La Crosse virus bite during the day but may bite at dusk and at dawn,” said Dr. Abelardo Moncayo, state medical entomologist. “People encountering mosquitoes should use insect repellents containing either DEET, Picaridin or oil of lemon eucalyptus. These ingredients are very effective when used in accordance to the label’s instructions.” 

According to recommended product guidelines, neither DEET nor Picaridin should be used on infants younger than 2 months; oil of lemon eucalyptus should not be used on children younger than 2 years of age. No product should be placed around the mouth or eyes at any age.  

“The best protection is still to use insect repellent and other personal protective measures, starting now and continuing through the end of mosquito season. Eliminating mosquito breeding grounds is important throughout the spring and summer,” said Dr. Moncayo. “There is still no vaccine or treatment for La Crosse virus, so prevention is crucial.”   

Simple steps can help reduce mosquitoes and mosquito breeding during mosquito season (April through October): 

• Don’t let water stand for over one week. Drain standing water in flower pots, toys, etc.

• Cleanup litter such as cans, bottles, buckets, tires and other trash that could hold water.

• Inspect and clean out rain gutters and downspouts so they will not hold water. 

• Clean bird baths and outdoor pet water bowls every two to three days.

• Keep windows and doors closed and repair screens to prevent mosquitoes from entering the house.