Eastern equine encephalitis (EEE) is a disease caused by a virus generally spread to humans through the bite of a mosquito. EEE can cause severe illness and possibly lead to death.
Click below to listen to a recent Podcast on EEE from Infectious Disease Specialist Amy Jaworek, M.D.
EEE does not occur every year, but based on mosquito sampling, a high risk of occurrence of human cases currently exists in 2019.
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The virus, which falls into the togavirus category, lives in the salivary glands of mosquitos. “It’s transmitted by mosquitoes that are endemic to our area, among other areas. One is called the Culex mosquito, and they are biting at nighttime around dusk in the area of Massachusetts and other surrounding states,” explains Dr. Amy Jaworek, Infectious Disease Specialist at Harrington.
Not every individual who is bitten by an infected mosquito will develop symptoms. For those who do, the first symptoms—which generally appear three to ten days after the infected mosquito bite—include muscle pain, high fever, and shaking chills.
If progressing to encephalitis, changes in mental status, confusion, weakness, and occasionally seizures may occur. These neurological symptoms are the main indicators that EEE may be present – and when you should seek medical care.
Children under 15 and persons over 50 are more prone to develop severe complications and symptomatic disease.
An official diagnosis is done by either a spinal tap or blood test.
Unfortunately, there is no cure for EEE. And outbreaks cannot be predicted—so risk must be mitigated when they do occur.
• Aerial and ground spraying has been used, particularly in the communities that are classified as “critical risk.”
• Wear long-sleeved shirts and pants
• Use insect repellent, specifically those with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), IR3535 (3-[N-butyl-N-acetyl]-aminopropionic acid) or oil of lemon eucalyptus [p-Menthane 3, 8-diol (PMD)] . DEET products should not be used on infants under two months of age and should be used in concentrations of 30% or less on older children. Oil of lemon eucalyptus should not be used on children under three years of age.
• Avoid the outdoors early in the morning and at dusk
• Remove potential breeding sites, such as garbage cans, clogged gutters, flowerpots, birdbaths or other items that contain standing water
• Repair holes in window screens
“The pesticide used is called Anvil 10+10, a product extensively tested and used in both ground-level and aerial spraying in the U.S. to control mosquitoes. Anvil 10+10 contains two ingredients: Sumithrin and Piperonyl butoxide.
Sumithrin is an ingredient similar to the natural components of the chrysanthemum flower which is also found in other pesticide products used indoors, in pet shampoos, and tick control treatments. Sumithrin is rapidly inactivated and decomposes with exposure to light and air, with a half-life of less than one day in the air and on plants. In soil, it degrades rapidly. Sumithrin has proven to be extremely effective in killing mosquitoes worldwide for over 20 years.
Piperonyl butoxide (PBO) serves to increase the ability of Sumithrin to kill mosquitoes. The product is registered by EPA and in Massachusetts for this use. It was used in previous aerial applications for mosquito control (2006, 2010, 2012). It is also used by some of the Mosquito Control Projects for ground applications.”
EEE Fact Sheet (English)