Eastern equine encephalitis (EEE) is a mosquito-transmitted virus. Normally, EEE is passed from bird to bird by swamp mosquitoes. On occasion, though, other species of mosquitoes will bite an infected bird and then a human, spreading the disease. EEE is relatively rare in humans, although there are occasional outbreaks in certain regions of the country. Fewer than 100 people have died from EEE in Massachusetts in the past 75 years, according to the Department of Public Health. Although the likelihood of contracting EEE is low, it is important to know the signs of the disease and seek medical attention as quickly as possible in the case of an infection. In humans, EEE causes encephalitis-an infection of the brain. "People with EEE may present with mental status changes, high fevers, headaches, stiff necks, muscle twitching, muscle weakness or paralysis," said William Charini, MD, PhD, a physician specializing in infectious diseases at Lahey Clinic Medical Center, North Shore. "Encephalitis can result in long-term cognitive and motor deficits, seizure disorders or even death." EEE infection in horses is often fatal. The virus cannot be transmitted from horses to humans. Antibiotics cannot be used to treat EEE. Treatment usually includes fluids, nutrition and medications to reduce fever and brain swelling. "With EEE, like almost all viral infections, treatment is supportive rather than curative," says Charini. The fatality rate for EEE is 35 percent, according to the Centers for Disease Control and Prevention, making it one of the most fatal mosquito borne diseases in the United States. Symptoms of EEE include high fever, confusion, headache, light sensitivity and uncontrollable movement. If you believe you or a family member has been infected with EEE, you should seek medical attention. The best way to prevent contracting EEE is to avoid being bitten by mosquitoes. Prevent breeding by freeing your yard of standing water. This means emptying any rainwater out of flowerpots, tires or other open containers. When you are outside, wear insect repellent. In areas with a large number of mosquitoes, wear long sleeves and pants, and consider using an insect repellent containing 30 percent DEET. "Prevention is key in EEE," said Charini. "If you are able to keep mosquitoes from biting you, you will have eliminated the risk of contracting EEE."
For specific information for Massachusetts on EEE visit the Massachusetts Department of Public Health Web site. Additional information about EEE can be found on the Centers for Disease Control and Prevention Web site.