Signs and symptoms of EEE virus disease usually appear within 4 to 10 days after a bite from an infected mosquito. EEE virus infection can result in a systemic (flu-like) illness, or it can attack the nervous system, causing inflammation in the brain or the membranes that surround the brain and spinal cord. Some people who become infected with EEE virus may not develop any symptoms.

Symptoms of systemic EEE virus infection appear abruptly and include fever, chills, body aches, joint pain, and fatigue. People with systemic EEE virus infection are usually sick for 1 to 2 weeks and can recover completely. In some older children and adults, systemic EEE virus infection can progress to infection of the nervous system; in infants, nervous system infection can occur without any signs of systemic illness first. Patients with nervous system infection can have fever, headache, vomiting, diarrhea, seizures, behavioral changes, drowsiness, and coma. 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.

Approximately one in three cases of EEE virus infection of the nervous system are fatal. Death usually occurs 2 to 10 days after onset of symptoms but can occur much later. Many people who recover will experience severe, permanent complications. These can include seizures, paralysis, mild to severe brain dysfunction, severe intellectual impairment, and personality disorders. Many patients with complications require long-term care and die within a few years.

Diagnosis of EEE virus disease is based on the patient’s signs and symptoms and appropriate laboratory testing. If you think you have EEEV disease, contact your healthcare provider.

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

The best way to prevent EEE virus disease is to avoid mosquito bites. See our mosquito prevention page for more information.

If evidence of widespread EEE virus activity is detected in Northern Indiana, IDOH may coordinate aerial application of pesticide as an emergency measure to reduce the risk of EEE virus infection. IDOH will not initiate aerial pesticide application in any jurisdiction without the explicit invitation and consent of county commissioners and Tribal representatives in affected areas.