By CAROL RYAN DUMAS
BOISE, Idaho -- Two Boise-area horses, one near Parma and one near Meridian, have tested positive for West Nile virus.
Both showed neurological symptoms consistent with the disease and tested positive within this last week, said Scott Leibsle, deputy state veterinarian with Idaho State Department of Agriculture.
Neither horse had been vaccinated for the virus, he said
Most West Nile cases are detected in horses that have not been vaccinated, and this year is a perfect example, he said.
Equine vaccinations for West Nile are readily available, effective and inexpensive, $20 to $30 per horse, and Leibsle advises horse owners to contact their veterinarians about vaccination.
West Nile virus causes an inflammation in the blood vessels of the brain. While there are antiviral drugs, they are largely ineffective in horses and cost prohibitive. Treatment consists of supportive care -- anti-inflammatory drugs and intravenous fluids, he said.
The virus is carried by birds and spread through mosquitoes. Horses, like humans, are terminal vectors and cannot spread the disease to other animals or humans, he said.
In addition to the two horses, the virus has been detected in mosquitoes in six Idaho counties -- Ada, Canyon, Owyhee, Payette, Twin Falls and Washington counties -- according to the Idaho Department of Health and Welfare.
Last year, West Nile virus was detected in nine horses in Idaho between Aug. 21 and Sept. 20, Leibsle said.