WATERLOO -- West Nile virus cases among horses have been drastically cut this year due to an aggressive vaccinating and public relations campaign, state agriculture officials said.

The latest state figures show 16 horses in 16 counties have contracted the mosquito-borne neurological disease. At this time last year, nearly 90 horses were inflicted with the illness.

By the end of 2002, there were 1,157 confirmed equine cases of West Nile. About 25 percent of the horses died.

Iowa Department of Agriculture and Land Stewardship spokesperson Machelle Shaffer said the high number of cases and deaths last year scared horse owners straight. People who were apprehensive about spending the $40 or so to inoculate their animals because the disease was so new -- discovered in the U.S. in 1999, making its way to the Midwest a few years later -- did so in droves at the end of last year and this spring.

"(The Ag department) did an extraordinary case of getting the word out to vaccinate. People saw it being done, and they wanted to take every precaution," Shaffer said.

Besides flooding the media with information and stories about the dangers of the disease, Shaffer said the department utilized the Iowa Rapid Veterinary Information Network to notify the state's veterinarians.

State officials created IRVIN -- a list of e-mail addresses and fax numbers for every vet in the state -- in late 2001 to help curb the threat of bioterrorism by spreading information quickly, like how to combat foot and mouth disease. They used IRVIN to urge horse owners to vaccinate.

"It's been phenomenal. We've updated vets on West Nile and pseudo rabies," Shaffer said. "Keep in mind there's still a couple of months (of mosquito season) to go. … But compared to last year, we're in a better position."

The virus causes the brain to swell. Infected horses exhibit symptoms like stumbling, muscle twitching, listlessness and excessive yawning. In severe cases, convulsions set in, and a horse can literally beat itself to death.

For horses that haven't been vaccinated, the two-shot process takes five to six weeks to become fully effective. A yearly booster also is required.

"Horses that are vaccinated and receive boosters at the designated intervals have the highest level of protection against the West Nile Virus," said Lynn Bixler in a press release, marketing manager for Equine Biologicals at Fort Dodge Animal Health, maker of the vaccine. "Millions of horses (nationwide) already have been safely vaccinated. Unfortunately, millions more are still at risk."