Ohioans are being encouraged to vaccinate their horses this month to protect them from West Nile virus.

Horses need to be vaccinated twice -- three to six weeks apart -- for the initial vaccination, said William Saville, an Ohio State University Extension veterinarian. Animals vaccinated last year need their yearly booster shot.

Show horses, race horses and any other horses under intense training should get two booster shots annually -- in April and late July.

Last year, more than 600 horses in Ohio were infected by the virus, which attacks the animals' brains and spinal cords. Thirty-five percent of those animals died or were euthanized.

In horses, symptoms of West Nile include loss of appetite; aimless wandering; depression; convulsions; stiffness; lethargy; fever; lameness; inability to swallow; circling; hyper-excitability; wobbliness; an inability to walk, rise or lie down; lack of coordination and coma.

The vaccine costs $18 to $25 per dose, plus the fee for the veterinarian to visit the farm.

Saville said horse owners can reduce the risk of West Nile by keeping their animals indoors at dusk and dawn when mosquitoes are most active. Lights should be turned off in stables, and all birds should be kept out of the stables.

Owners also can use chemical repellants and should eliminate mosquito-breeding areas, he said.

-- BOB DOWNING