Eastern equine encephalitis
Eastern equine encephalitis is spread to humans and horses by infected mosquitoes. It is among the most serious in a group of mosquito-borne viral diseases that can affect the central nervous system. The most effective way to prevent infection with E... (Photo Credit: U.S. Army) VIEW ORIGINAL

ABERDEEN PROVING GROUND, Md. -- Army public health officials are offering new tips to prevent the spread of Eastern equine encephalitis, which is a rare disease that is spread to humans and horses by infected mosquitoes. The Army Public Health Center posted an updated fact sheet on the disease to its website Sept. 19. EEE is among the most serious in a group of mosquito-borne viral diseases that can affect the central nervous system and cause severe complications and even death.

The update follows the U.S. Centers for Disease Control and Prevention report of 27 EEE cases in 2019 from six states, including Massachusetts, Michigan, Rhode Island, New Jersey, Connecticut and North Carolina. The cases resulted in six deaths.

According to the CDC, from 2009 to 2018, the U.S. reported an average of seven EEE cases annually. EEE transmission is most common in and around freshwater hardwood swamps in the Atlantic and Gulf Coast states and the Great Lakes region.

On Sept. 19, a pool of mosquitoes collected at Joint Base McGuire-Dix-Lakehurst, New Jersey, tested positive for EEE and West Nile virus.

Unlike the Zika virus, which can be transmitted by mosquitoes from human to human, EEE can only be transmitted by mosquitos from infected birds. Those who work around swamps or marshy areas can be exposed to bird-biting mosquitoes and are, therefore, at higher risk for contracting this disease.

"Humans and horses are what we call dead-end hosts," said Rosanne Radavich, an entomologist with APHC. "This means if the disease gets into us, mosquitos don't pick it up and move it around again. The important thing for us is to raise awareness so Soldiers understand the risk and take proper precautions."

APHC entomologists stress it is important for Soldiers to use the Department of Defense Insect Repellent System to prevent mosquito bites. This includes wearing the Operational Camouflage Pattern uniforms that are factory treated with permethrin insect repellent; keeping uniform sleeves rolled down; sleeping under a permethrin-treated bed net; and applying DoD-approved insect repellents on any exposed skin.

"We strongly encourage people to use insect repellent on their exposed skin, including face, neck and hands, and for Soldiers to wear their uniform correctly," said Radavich.

According to the APHC fact sheet, many people who are infected with EEE virus show no symptoms. In other people, symptoms range from mild flu-like illness (with fever, headache and sore throat) to encephalitis (inflammation of the brain), coma and death. Symptoms usually appear four to 10 days after the bite of an infected mosquito. Diagnosis can be confirmed by testing blood or spinal fluid.

The fact sheet also cautions that anyone developing symptoms such as a sudden high fever, unusually severe headache, nausea or vomiting, should seek medical attention immediately.

Although some people may feel panicked by the increased news coverage around EEE, APHC entomologists stressed this illness has been around for a long

time, is not spreading to new states, and is part of a reoccurring annual


"The first killing frost will bring this year's cycle to an end," said Thomas Burroughs, an APHC entomologist. "However, because the infection is still maintained in the bird population it never completely goes away."

Anyone interested in finding out more information about EEE is encouraged to review the APHC fact sheet at https://phc.amedd.army.mil/PHCResourceLibrary/EasternEquineEncephalitis_FS_18-020-0919.pdf or review the information on the CDC website at https://www.cdc.gov/EasternEquineEncephalitis/.

The Army Public Health Center focuses on promoting healthy people, communities, animals and workplaces through the prevention of disease, injury and disability of Soldiers, military retirees, their families, veterans, Army civilian employees, and animals through population-based monitoring, investigations, and technical consultations.

Related Links:

Centers for Disease Control and Prevention EEE Fact Sheet