Information On Eastern Equine Encephalitis

What is Eastern Equine Encephalitis or EEE?

Eastern Equine Encephalitis is an infectious disease that affects the brain of horses. The disease is caused by a virus which attacks the brain, destroys some nerve cells and cause brain inflammation and swelling.

Can people be get EEE?

Yes, people can get a disease that looks like the disease in horses.

What type of illness does EEE cause in people?

The majority of the people who get infected with the virus have no illness or at most, have an infection similar to a mild flu with fever, headache and fatigue. Rarely the virus will multiply in the central nervous system and causes a brain disease (called encephalitis). The symptoms are high fever, headache, drowsiness, irritability, and sometimes loss of muscular power, in arms and legs, double vision, impairment of speech, hearing or balance.

How common is EEE?

EEE is a rare disease in Louisiana. It occurs in small outbreaks in the late summer. Several years may go by without outbreaks. Outbreaks usually start with horses and are followed by a few human cases. In 1999 there were 2 cases in humans and over 100 in horses, in 2000 there were 5 cases in horses and no cases in humans.

How do persons get infected with EEE?

The EEE virus infects wild birds and is passed on from bird to bird by mosquitoes. EEE does not cause any illness in these wild birds. During late summer and early fall mosquitoes leave the swamps for drier forested habitats. If they are in high numbers these mosquitoes which usually do not bite people or horses will do so and transmit the infection to them.

EEE is not transmitted from horse to horse or from horse to human because the virus does not reach sufficiently high levels in the blood to be infectious to mosquitoes.

How can EEE infection be diagnosed?

The diagnosis of EEE is confirmed by lab tests performed in the blood or the spinal fluid.

How is EEE infection treated?

There are no drugs that would kill the virus and stop the infection. The treatment consists of helping the patient survive through the complications caused by the disease.

Are there long-term consequences of EEE infection?

While EEE is usually a mild infection, in some rare cases it can cause death or serious brain damage with sequelae that remain. Some improvements may be seen after some time.

1. Avoid outdoor activities when mosquitoes are the most active or wear long sleeve shirts and long pants and avoid dark colors which attract mosquitoes.
2. Apply insect repellent (with NN diethyl-m-toluamide -DEET- or dimethyl phtalate). Follow the instructions on the bottle. Do not exceed the dose particularly in children.
3. Spend nights in well maintained buildings with screened doors and windows. If the building is not insect-proof (tent for example) sleep under a mosquito net. Make sure that the net is not torn and that no mosquitoes are trapped inside. Insecticide sprays, electric insecticide dispenser with pyrethroid tablets and pyrethroid mosquito coil are useful but do not replace a good mosquito net.

What can be done to prevent being infected?

Because there is no specific treatment for EEE, control of epidemics relies solely on personal protective measures against mosquitoes, spraying to kill mosquito adult, applying pesticides against larvae or reducing the breeding areas for larvae (standing water). If sufficient numbers of adult mosquitoes are killed, virus transmission can be interrupted.

1. Avoid outdoor activities when mosquitoes are the most active or wear long sleeve shirts and long pants and avoid dark colors which attract mosquitoes.
2. Apply insect repellent (with NN diethyl-m-toluamide -DEET- or dimethyl phtalate). Follow the instructions on the bottle. Do not exceed the dose particularly in children.
3. Spend nights in well maintained buildings with screened doors and windows. If the building is not insect-proof (tent for example) sleep under a mosquito net. Make sure that the net is not torn and that no mosquitoes are trapped inside. Insecticide sprays, electric insecticide dispenser with pyrethroid tablets and pyrethroid mosquito coil are useful but do not replace a good mosquito net.