SMH physicians recommend precautions against LaCrosse Encephalitis

Summer time is mosquito time. While the vast majority of mosquito bites result in nothing more than an annoyingly itchy, occasionally painful bump, there is a real risk of being stung by a mosquito that carries disease. In Nicholas County, that disease is more likely to be LaCrosse Encephalitis (LAC), and it should not be taken lightly.

“In the last several years West Nile virus has attracted a great deal of attention nationwide,” said Kevin Dickenson, MD, chief of staff at Summersville Memorial Hospital. “While this is a very serious condition, residents of West Virginia are at much greater risk for contracting LAC from mosquito-human contact.” Named after LaCrosse, Wis., where it was first recognized in 1963, the disease is most common in the upper midwestern and the Appalachian regions of the United States, including West Virginia. 

Both West Nile virus and LAC are in the class of diseases called arboviruses, short for arthropod-borne viruses, which can affect the central nervous system and cause severe neurologic complications, including seizures. Most people who contract LAC will make a full recovery, with no lasting side effects; however, in rare instances, the most serious cases can lead to death. Immediate medical treatment should be sought by anyone who believes he has contracted LAC.

Symptoms of LAC are fairly pronounced, appearing anywhere from day five to 15. The most common symptoms include a high fever (102° to 105°), severe frontal headache, and vomiting. Lethargy and irritability are other common symptoms, and people with severe disease – often children – may have seizures, coma, paralysis and lasting brain damage.

Those at particular risk for contracting LAC from an infected mosquito include people who live or visit woodland areas, and people who work or spend a lot of time outdoors are at increased risk. Children have a significantly increased risk, says Mark Tomsho, MD, a pediatrician on staff at Summersville Memorial Hospital who has treated more than 150 patients with the disease.

The immature, pre-adolescent nervous system is much more susceptible to contracting the disease,” Dr. Tomsho explains, noting that 75 percent of cases occur in children under age 12, and the greatest risk is to children ages 3 to 12.

Fortunately, there are several simple precautions that can greatly reduce the risk of being stung by a LAC-infected mosquito. “A significant impact can be made by removing standing water from tree holes, tires, cans or other small, rimmed containers from your property,” Dr. Tomsho says, adding that, contrary to popular belief, LAC-carrying mosquitoes do not live in swampy areas or near swimming pools. “The types of mosquitoes that carry LAC have a limited travel range – approximately 300 feet.
By eliminating water within that range, you eliminate breeding conditions.”

Dr. Tomsho also urges people who are going to be outdoors to apply DEET-containing insect repellant to their skin and to their children’s skin. (Note: The American Academy of Pediatrics says that DEET-containing products should not be applied to infants under two months of age.)

Products with a DEET concentration of 10 to 30 percent are most desirable. Generally, a repellant containing 10 percent concentration of DEET can be expected to provide protection up to two hours, while a 30 percent concentration will provide protection for four to five hours.

Dr. Tomsho recommends against using combined DEET-sunscreen products. “Because sunscreen is easily washed off, people tend to reapply it often. But DEET is absorbed into the skin, so reapplication of DEET is not desirable,” he explains.

Because LAC is a virus, antibiotics are not effective against it. Rather, patient care focuses on hospitalization where symptoms and complications – such as swelling of the brain, seizures and breathing complications – can be treated immediately.

Dr. Tomsho notes that his pediatric practice has seen a decrease in the number of LAC cases in recent years. He attributes this to several factors, including drier weather, a natural shift in mosquito-borne disease patterns, and, importantly, a public health education campaign within Nicholas County to raise LAC awareness.

“This campaign made a real impact in the decrease in cases, but there’s always a chance for an another outbreak. It’s important to be vigilant and take all precautions to guard against infection.”