Venezuelan Equine Encephalitis

What is Venezuelan Equine Encephalitis? 

Venezuelan Equine Encephalitis is a mosquito-borne viral pathogen that causes Venezuelan equine encephalitis or encephalomyelitis (VEE). Horses infected with VEE develop viremia high enough to transmit to mosquitoes. Because they are amplifying hosts, horses play an important role in the epidemiology of the disease in both horses and humans.

Clinical Signs: Highly variable and similar to other arboviruses such as EEE and WNV.

  • Moderate to high fever 102.5–104.5°F (39.17–40.28°C) 
  • Inappetence
  • Diarrhea
  • Dysphagia 
  • Head pressing 
  • Circling 
  • Blindness 
  • Dementia 
  • Seizures 
  • Rapid behavioral changes: somnolence, hyperexcitability, mania, self-mutilation 
  • Cranial neuropathy: nystagmus, facial nerve paralysis, and weakness of the tongue and pharynx
  • Coma 
  • Death

Diagnosis: The diagnosis is by serologic evaluation for antibodies or virus culture or histologic detection of the virus. 

Treatment: Symptomatic care is the only treatment.

Prevention: A vaccine is available. VEE is not endemic in the United States and is considered a foreign disease.