Agent

Virus

Vector

Birds

Route

Mosquitoes

Dead End Host

Horses, humans

Systems Affected

Spinal cord, brain

Symptoms

• Fever and depression
• Diarrhea
• Overall drowsy appearance and no desire to move
• Muzzle twitching
• Self-mutilation, hyperexcitability, irritability, and a refusal of food and water
• Central nervous system signs of incoordination, head pressing, circling, paralysis, convulsions, and coma
• Death

Treatment

Intravenous fluids and anti-inflammatory drugs to decrease brain swelling

Prevention

Vaccination, removal of mosquito breeding areas, keeping horses indoors during peak mosquito activity periods

For more information, see West Nile Virus in Horses.