Shown under a microscope is the eastern equine encephalitis virus.  Photo from Centers for Disease Control and Prevention
Shown under a microscope is the eastern equine encephalitis virus. Photo from Centers for Disease Control and Prevention
Eastern equine encephalitis (EEE) has been detected in northern Indiana, but not yet in Kosciusko County.

County Health Administrator Bob Weaver on Thursday said the mosquitoes that carry EEE are usually found in boggy and swampy areas. So far, testing in Kosciusko County has turned up negative, but testing will continue.

“I’m trying to keep in touch with the state so if we find a pocket of it here, maybe we can get state funding to spray like in the other counties,” he said.

As of Tuesday, 11 cases have been confirmed in horses – nine in Elkhart County and two in LaGrange County, according to a news release from the ISDH. The Elkhart, LaGrange and Noble county health departments and the Indiana State Department of Health have been working together to monitor EEE activity.

Due to the detection of EEE activity in the area and the occurrence of human EEE cases in nearby Michigan counties, health officials performed targeted mosquito control Wednesday night, using aerial spraying to help protect residents from EEE. Due to a technical problem, the treatment area in LaGrange and Noble counties was sprayed again Thursday evening.

Mosquito-control professionals applied an approved pesticide, Dibrom, as an ultra-low volume (ULV) spray. ULV sprayers dispense very fine aerosol droplets that stay suspended in the air and kill adult mosquitoes on contact. Dibrom has been registered by the U.S. Environmental Protection Agency since 1959 for use in the United States. Dibrom immediately begins to break down upon release of the spray droplets in the open air and breaks down rapidly in water and in sunlight, according to the release.

Protecting public health is the primary goal of the decision. The spray area is centered around the area where equine cases have been confirmed. This activity is not expected to pose a risk to humans.

While the spraying is expected to kill 90 percent of mosquitoes, residents in the area are urged to continue to take precautions until the first hard freeze.

EEE virus can be transmitted in Indiana by mosquitoes in the genus Coquillettidia, but some members of the genus Aedes may also play a role in transmission to humans and animals. These mosquitoes become infected when they feed on infected wild birds. Infected mosquitoes can then spread EEE virus to people, horses and other mammals. Once infected, people and other mammals are “dead-end hosts,” which means that they do not pass the virus on to other biting mosquitoes, according to the ISDH.

While rare, EEE virus can cause serious illness and has a fatality rate of about 33 percent in people, the release states. People infected with EEE virus can develop severe inflammation in the brain.

Signs and symptoms of EEE virus disease usually appear within four to 10 days of a bite from an infected mosquito. EEE virus infection can result in one of two types of illness, systemic or encephalitic (involving swelling of the brain). It is possible that some people who become infected with EEE virus may not develop any symptoms.

Symptoms of systemic EEE virus infection appear abruptly and include chills, fever, body aches and joint pain. People with systemic EEE virus infection are usually sick for one to two weeks and recover completely if the infection does not spread to the central nervous system. In some older children and adults, systemic EEE virus infection can progress to encephalitis (inflammation of the brain). In infants, encephalitis can happen abruptly.

Many people who recover will experience severe ongoing complications. People who are younger than 15 years and older than 50 years are at the greatest risk of severe disease if infected with EEE virus.

No specific medication is available to treat EEE virus disease. People with severe illness usually require hospitalization, supportive care, and/or rehabilitation.

For more information about EEE, visit the CDC’s website at