Several cases of La Crosse encephalitis, a disease spread by bites from infected mosquitoes, have turned up in scattered locations across south-central West Virginia in recent days, according to Dr. Jim McJunkin with WVU Pediatrics at CAMC’s Women and Children’s Hospital.
While most people infected with the disease do not feel sick, those with mild symptoms may experience headaches, fever, nausea, vomiting, drowsiness or confusion. In severe cases, those infected may have seizures or become comatose, according to McJunkin.
La Crosse encephalitis can be fatal, but rarely is. From 2015 to 2018, the most recent period for which records are available, no deaths from the disease were reported in the United States, according to the Centers for Disease Control. Children under age 15 have the highest risk of contracting the disease, McJunkin said, and may have seizures or other problems after they get well.
McJunkin said La Crosse encephalitis cases typically begin to appear in West Virginia in early July and continue through October. While the incidences of the disease in the state have been declining in the past decade, a higher-than-normal number of cases have been reported in the state for this time of year.
The disease is spread by tree hole mosquitoes, so named for their habit of breeding in tree cavities capable of retaining stagnant water. The mosquito variety also makes use of human-made stagnant water sites, such as discarded tires, along with buckets, garbage containers, bottles and cans left outside to collect rainwater.
Children who live near such standing water sources, along with those who live or camp near the woods, are most at risk of contracting the disease, according to the Charleston pediatrician. He attributes the recent reduction in La Crosse encephalitis cases to the state Health Department and the state Department of Environmental Protection’s Rehabilitation Environmental Action Program creating public information and tire disposal programs designed to reduce the number of mosquito breeding sites.
McJunkin said a number of steps can be taken by the public to further reduce breeding habitat for the mosquitoes. They include “getting rid of old tires and trash around your home, punching holes in the bottoms of trash barrels so they won’t hold water, cleaning and emptying water from flowerpots, birdbaths, swimming pool covers, buckets and barrels at least once or twice a week,” he said.
McJunkin, whose research on La Crosse encephalitis was first published in the New England Journal of Medicine in 2001, also suggested cleaning gutters, periodically changing the water in, or draining, swimming pools, and wearing long-sleeved shirts and long pants when outdoors.
States in the Midwest and Mid-Atlantic regions report the highest incidences of La Crosse encephalitis, according to the Centers for Disease Control and Prevention, with West Virginia recording the fourth-highest rate of contracting the disease, behind Ohio, Tennessee and North Carolina. Even so, only 77 cases of neuroinvasive LaCrosse encephalitis were recorded in the state between 2009 and 2018, according to the CDC.
While incidences of the disease are higher in West Virginia than most states in the region, due mainly to its forested terrain, “it’s still quite low, compared to Coronavirus disease,” McJunkin said, making “the benefits of our state’s wonderful outdoors absolutely worth enjoying.”