A Luzerne County horse tested positive for Eastern Equine encephalitis in mid-September. EEE, also known as sleeping sickness, is a zoonotic alphavirus that affects humans, horses and birds and is spread by mosquitoes.

Symptoms in horses occur one to three weeks after infection, and begin with a fever that may reach as high as 106 °F (41 °C). The fever usually lasts for 24–48 hours.

Nervous signs appear during the fever that include sensitivity to sound, periods of excitement, and restlessness. Brain lesions appear, causing drowsiness, drooping ears, circling, aimless wandering, head pressing, inability to swallow, and abnormal gait. Paralysis follows, causing the horse to have difficulty raising its head. The horse usually suffers complete paralysis and death two to four days after symptoms appear. Mortality rates among horses with the eastern strain range from 70 to 90 percent.  The disease is transmitted only by mosquitoes and cannot be transferred from horse to horse or equine to human.

There is no treatment other than palliative care, but a vaccine is available. Properly administered vaccinations are effective for only one year, thus, booster shots are required on an annual basis. Newly vaccinated animals require a two-shot series administered 2-4 weeks apart before protection can be guaranteed.