Alabama Agriculture and Industries Commissioner John McMillan announced that since June, several positive cases of Eastern equine encephalitis (EEE) have been found in Alabama in birds and horses.

"We are entering into the time of year that makes us extremely vulnerable to the spread of mosquito-borne viruses and we need to protect our livestock and ourselves," stated McMillan. "I want to encourage horse owners to vaccinate their horses for both EEE and West Nile virus (WNV) as soon as possible."

A viral disease, EEE affects the central nervous system and is transmitted to horses by infected mosquitoes. Its fatality rate in horses is 75-95%. The course of EEE can be swift, with death occurring two to three days after onset of clinical signs despite intensive care. Horses that survive might have long-lasting impairments and neurologic problems. Clinical signs of EEE include moderate to high fever, depression, lack of appetite, cranial nerve deficits (facial paralysis, tongue weakness, difficulty swallowing), behavioral changes (aggression, self-mutilation, or drowsiness), gait abnormalities, or severe central nervous system signs, such as head-pressing, circling, blindness, and seizures.

Clinical signs for WNV include flu-like signs, where the horse seems mildly anorexic and depressed; fine and coarse muscle and skin fasciculations (twitching); hyperesthesia (hypersensitivity to touch and sound); changes in mentation (mentality), when horses look like they are daydreaming or "just not with it"; occasional somnolence (drowsiness); propulsive walking (driving or pushing forward, often without control); and "spinal" signs, including asymmetrical weakness. Some horses show asymmetrical or symmetrical ataxia (incoordination on one or both sides, respectively). Equine mortality rate can be as high as 30-40%. The USDA Animal and Plant Health Inspection Service reported 83 cases of WNV in U.S. horses in 2011