Equiloid Innovator

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 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%. In humans, symptoms include high fever, muscle pain, altered mental status, headache, meningeal irritation, photophobia, and seizures, which occur three to 10 days after the bite of an infected mosquito.