A Thoroughbred yearling from the Lexington area has died of West Nile Virus. It is the first time this year West Nile has been identified in a horse in Kentucky, according to the state Department of Agriculture's office of the state veterinarian.The University of Kentucky Livestock Disease Diagnostic Center made a diagnosis based on the animal demonstrating clinical signs of the disease, polymerase chain reaction (PCR) test results indicating a positive WNV infection, and brain lesions suggesting a myeloencephalomyelitis, Ford said."The wet spring we experienced established breeding grounds for mosquitoes, which transmit West Nile," Agriculture Commissioner Billy Ray Smith pointed out. "We are not surprised to see the virus return to Kentucky, and we are working with farmers, public health officials, and federal authorities to contain it."The horse reportedly had been vaccinated twice for West Nile Virus in accordance with the manufacturer's recommendations, State Veterinarian Dr. Don Notter said.The Agriculture Department is working with the Kentucky Veterinary Medical Association, the Kentucky Thoroughbred Association, the Kentucky Department for Public Health, the Division of Emergency Management, the Department of Fish and Wildlife Resources and other agencies and organizations to gather information and distribute it to farmers, veterinarians, and the public.The horse industry's Equine Emergency Task Force has been notified, said David Switzer, executive director of the Kentucky Thoroughbred Association.Ford said two other cases of possible West Nile Virus are open, pending test results. The state veterinarian's office has conducted 13 field investigations for possible West Nile Virus so far this year, he said. Kentucky reported eight positive horses in 2001.Also Thursday, the Department for Public Health reported that a dead blackbird in Oldham County, Ky., outside Louisville, was found to have West Nile Virus. The state public health department announced Tuesday that two dead birds, both grackles, in Metcalfe County, Ky., tested positive for West Nile.West Nile Virus causes encephalitis, or inflammation of the brain, in horses, humans, birds, and other warm-blooded animals. It is transmitted by mosquitoes that acquire it from infected birds. The Department for Public Health said that no cases of West Nile Virus in humans have been reported in Kentucky.Even in areas where mosquitoes carry the virus, less than 1% of mosquitoes are infected, and severe illness occurs in less than 1% of people bitten by infected mosquitoes, the Department for Public Health said. People over 50 and those with weak immune systems are especially susceptible to the disease, according to the state public health department.West Nile primarily is a disease of wild birds, particularly crows, blue jays, and birds of prey, so it is standard procedure to examine dead birds for signs of the virus. To report a dead bird in Kentucky, contact the Kentucky Department of Fish and Wildlife Resources at 1-800-858-1549, extension 352.Dr. Notter said horse owners should consult with their veterinarians about whether to vaccinate their horses for West Nile and about mosquito control measures that they can take. He said owners and farm managers should consider putting horses up in the early evening, when mosquitoes are most active.To reduce the risk of infection, the Department for Public Health said, people should stay indoors when mosquitoes are most active–dawn, dusk, and in the early evening; wear long-sleeved shirts and long pants outdoors; and spray clothing and bare skin with repellents containing permethrin, or DEET.State authorities said the best way to combat West Nileis to take away areas of standing water where mosquitoes can breed. The Department for Public Health recommends the following steps: - Remove all discarded tires on your property. Used tires are one of the primary breeding areas for mosquitoes. - Dispose of tin cans, plastic containers, ceramic pots, or similar water-holding containers. - Drill holes in the bottom of recycling containers left outdoors. - Make sure roof gutters drain properly, and clean clogged gutters in the spring and fall. Roof gutters can produce millions of mosquitoes each season. - Turn over plastic wading pools and wheelbarrows when not in use. - Change water in birdbaths. - Clean vegetation and debris from edges of ponds. - Clean and chlorinate swimming pools, outdoor saunas and hot tubs. Aerate or add fish to ornamental ponds. Remember to drain water from pool covers and tarps. - And, use landscaping to eliminate standing water that collects on your property.