KNOXVILLE, Tenn. – The Tennessee departments of Agriculture and Health are urging horse owners to be on the alert and review vaccination records for eastern equine encephalitis (EEE) and other mosquito-borne diseases including West Nile virus (WNV). 


“Outbreaks of viral encephalitis in horses are a seasonal occurrence due to the prevalence of mosquitoes in late summer and early fall,” said Dr. Ron Wilson, state veterinarian with the Agriculture Department.  “Horse owners should be aware of symptoms of viral encephalitis and consult their local veterinarian should their horse develop any of the signs associated with this group of diseases.”   


Several states have reported cases of EEE in horses this season.  Tennessee’s first confirmed case of 2007 was reported this week in Blount County.  Up to 90 percent of horses infected with EEE virus can die. 


Another mosquito-borne disease, West Nile virus infection, has been seen in horses across the state, including East Tennessee, in 2007.  Wilson says the spread of WNV has heightened awareness and concern for other nervous system diseases in horses.  Many of the signs of EEE overlap with those described for WNV in horses and include: 


·         Decreased alertness

·         Blindness or impaired vision

·         Aimless wandering or circling

·         Head pressing

·         Inability to swallow

·         Weakness, paralysis or convulsions


“Definitive diagnosis is important in tracking the spread of viral infections,” said Wilson.  “It requires a commitment on the part of horse owners working with their local veterinarian and verifying test results through laboratory analysis.”   


Vaccines are available to protect against EEE and WNV in horses.  Horse owners are encouraged to review their records and consult with their veterinarian regarding immunization for these diseases. Additionally, insect repellents can be used on horses but may have limited effectiveness.  Screened stalls can also help reduce exposure of animals to mosquitoes.  


Although humans cannot contract viral encephalitis directly from infected horses, according to Dr. Abelardo Moncayo, state medical entomologist with the Department of Health, viral encephalitis does pose a public health risk, and people should also take proper precautions.