What is Eastern Equine Encephalitis & How is it Treated? | Types, Causes, Symptoms of EEE

Eastern Equine Encephalitis is a viral disease that was first discovered in 1933 in horses.⁽¹⁾ This disease gets transmitted when an infected mosquito bites a human being.⁽¹⁾ The mosquito gets this virus after biting a bird with this infection.⁽¹⁾ Humans and horses are more prone to Eastern Equine Encephalitis.

Many patients having Eastern Equine Encephalitis virus will not have symptoms and suffer from mild types of this disease, known as systemic infection. This condition can mimic the flu; however, around 5% of patients who suffer from Eastern Equine Encephalitis can develop an extremely rare and potentially fatal infection that results in inflammation and swelling of the brain, i.e. encephalitis.

Eastern equine encephalitis is named because this disease is more prone to develop in the eastern portion of the USA;⁽²⁾ however, Eastern Equine Encephalitis (EEE) can also be seen in the in the Great Lakes region and along the Gulf Coast.

The Eastern Equine Encephalitis virus was first discovered in 1933 and was initially isolated from the tissue of CNS in human beings in 1938. Human beings and horses are more vulnerable to the Eastern Equine Encephalitis virus.

After the virus enters the body, it replicates and travels in the bloodstream. Very rarely, this virus can permeate the blood-brain barrier and cause infection in the brain, resulting in brain tissue swelling, which is known as encephalitis.

There are four variants of the virus worldwide, but only one is indigenous to North America and the Caribbean. This variant of the Eastern Equine Encephalitis virus is also responsible for causing the majority of the cases of Eastern Equine Encephalitis. The other three types of this virus are seen in South and Central America and mainly are responsible for causing equine illness.

NO. The Eastern Equine Encephalitis virus is not contagious and does not spread by human-to-human contact. The virus also does not spread from animals to people; or people to animals.

The virus of Eastern Equine Encephalitis is transmitted when infected female mosquitoes bites someone and these mosquitoes are prevalent in swampy areas and marshlands and commonly feed on birds.^{(1, 2, 3)}

The source of Eastern Equine Encephalitis virus is Birds, which can become infected without displaying any symptoms of EEE. The virus then gets passed to the mosquitoes from these infected birds, after which this virus gets spread to human beings and horses through the bite of the infected virus.

Individuals who are more than 50 years of and less than 15 years of age are higher risk of developing severe Eastern Equine Encephalitis infection.⁽⁴⁾ People having weak immune systems are also at a higher risk for developing Eastern Equine Encephalitis infection.

Symptoms of Mild Eastern Equine Encephalitis: The mild form of EEE is similar to the flu, with symptoms, such as chills, abrupt increased fever and aches in the muscles and joints.⁽⁴⁾ The duration of the mild form of Eastern Equine Encephalitis can be up to two weeks.

Symptoms of Acute Eastern Equine Encephalitis: The acute or severe type of Eastern Equine Encephalitis also begins with symptoms resembling the flu; however, about four days after the development of these symptoms, characteristics of brain infection can be seen. These symptoms of brain infection seen in severe form of Eastern Equine Encephalitis consist of: bad headache, confusion and extreme drowsiness.⁽⁴⁾ There can be rapid worsening of the complications resulting seizures, coma and even death in some cases.

Lumbar Puncture (Spinal Tap): In this test the CSF fluid sample is taken and sent to the lab to analyze whether it contains EEE virus or not.

CT scan/ MRI scan: CT or MRI scan of the brain can also be done to look at the signs of inflammation.

Blood Tests: blood tests are also done to diagnose Eastern Equine Encephalitis by looking for increased levels of antibodies, which is an indication that our immune system is fighting a virus or a disease.

Unfortunately, there is no vaccine for prevention of EEE and brain infection in human beings.^{(4, 5)} However, a vaccine is present for prevention of Eastern Equine Encephalitis in horses,

The main aim of treatment of Eastern Equine Encephalitis is to reduce the intensity of symptoms as this viral infection progresses through its course. Patients suffering from severe form of Eastern Equine Encephalitis are treated by admission into intensive care unit, where a ventilator is used for the patient to help with the breathing problems associated with this disease. Patients suffering from a severe form of Eastern Equine Encephalitis can also be put into a medically induced coma.

Treatment for Eastern Equine Encephalitis also consists of medications that are given for treating seizures or to reduce the inflammation in the brain. However, after the virus has entered the nervous system, there are chances that the patient can suffer from neurological consequences. Majority of the deaths from Eastern Equine Encephalitis are due to swelling and pressure within the brain and spinal cord.

To prevent Eastern Equine Encephalitis, insecticides should be sprayed in areas where mosquitoes are abundantly found, such as in and around the marshy lands and swamps.^{(4, 5)} This will help in cutting down the chances of Eastern Equine Encephalitis; however, does not completely remove the risk of this illness.

Eradicate Stagnant Water: Any stagnant water needs to be removed, as it is a thriving place for mosquitoes.

Insect Repellent: Insecticides that contain picaridin or oil of lemon eucalyptus and DEET should be used.

Keep Your House Safe: If there are any holes in screens of your doors and windows, then repair them ASAP to prevent mosquitoes from entering your house and spreading this disease.

Watch When You Go Outside: Avoid any outdoor activities or going outside your home between dusk and dawn, as this is the time when the mosquitoes are most active. Even if you are going outside, make sure that your keep your skin protected by wearing long-sleeved shirts and long pants; socks and shoes.

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