THREAT TO HORSES VALLEY AWAITS ARRIVAL OF DREADED VIRUS.

Byline: Susan Abram Staff Writer

BURBANK - Jessie James stood quietly while veterinarian Susan Bauer checked her heartbeat with a stethoscope. The 7-year-old Welsh pony was in good health, Bauer declared.

But because the gray pony had been shipped recently from North Carolina, where West Nile virus infected seven horses last year, trainer David Josiah wants to know if Jessie James and the other 20 horses he cares for at the Los Angeles Equestrian Center are at risk and should be inoculated.

``All horses are at risk,'' Bauer tells him. ``But the vaccine doesn't protect the horses forever. It's only good for a year.''

As news that West Nile virus has hit as close as Colorado in the last few days, Valley horse lovers from Chatsworth to Burbank's Rancho equestrian neighborhood - where a third of all homes board horses - are relying on veterinarians like Bauer for any advice they can get.

Home to 600 show horses and ponies, the Equestrian Center's property runs close to the Los Angeles River, a breeding ground for mosquitoes that could spread West Nile virus.

Although officials from the Los Angeles County Vector Control District said mosquito numbers are down this summer - because of drought and an increased larvacide campaign and bird surveillance program - concern lingers among horse owners and trainers.

Bauer has already inoculated hundreds of horses with the first and only horse vaccine, placed on the market last year, she said.

At Mariposa Boarding Stables in Burbank, all 29 horses have been vaccinated, said owner Milie Simick.

``I think the majority of the people here are trying to get more information,'' Simick said. ``I would say the majority of the people are doing something about it.''

While California has seen no trace of the virus yet, the nation is in the midst of its third major outbreak of West Nile, a mosquito-borne virus that first appeared in New York City in 1999.

Its presence in the United States became a more serious threat this year, killing 10 people - seven from Louisiana alone - and has infected more than 160 people nationwide as it makes its way West.

Like humans, all horses infected with the virus do not become ill. But the rate of infection is higher - about 30 percent of horses infected come down with fever or serious symptoms associated with encephalitis, a potentially fatal swelling of the brain.

Horses that become ill are more often euthanized than saved, according to officials from the CDC, which does not keep statistics on horses and West Nile.

The potential economic impact of West Nile virus on Southern California's horse industry alone, home to the Santa Anita and Hollywood racetracks and Griffith Park ponies, could be staggering, said Dr. Gregory Ferraro, director of equine studies at the Veterinary School of Medicine at the University of California, Davis, where mosquitoes trapped in Southern California are tested for the virus. < Of the 6.9 million horses nationwide, California is home to 692,000.

``California isn't the largest horse state, but it's up there,'' Ferraro said. ``Horse racing alone generates $454 million a year in direct tax revenues. It would be a very large economical loss.''

Because West Nile is an emerging disease in the Western Hemisphere, scientists still do not understand why certain animals, such as horses and birds, primarily crows, remain most susceptible, Ferraro said.

But officials from UC Davis, the state's Department of Food and Agriculture and California Health Services said the state is ready for West Nile's appearance.

``The state has been preparing for three years,'' Ferraro said. ``West Nile is really not a bad disease compared to others. But if anything good comes out of it, it's that all of us are working together.''

During a horse show in Indio last winter, more than 150 horses were tested for West Nile virus, said Leticia Rico, spokeswoman for the state's Department of Food and Agriculture.

The agency is prepared to offer horse owners and trainers free blood testing through a grant from the CDC.

Locally, the county's health department also is prepared, but officials there say education is the best protection.

Horse owners are being told to eliminate standing water around barns and to spray the animals with mosquito repellent.

``We are organizing for the virus,'' said Dr. Patrick Ryan, chief of Veterinary Public Health and Rabies Control, for Los Angeles County. ``We're starting to do active surveillance and taking blood samples.''

The horse vaccine's maker, Kansas-based Fort Dodge, expects an increased demand as the virus moves west, said company spokesman Rob Daily.

``This is the best time to vaccinate in California, before the virus appears,'' he said.

The vaccine, which costs $25 per dose, has so far only shown mild side affects in .01 percent of all horses and has been issued a conditional license for six months. It's expected to be approved by the federal Department of Agriculture soon, Daily said.

``We are optimistic we'll be fully licensed,'' he said. ``We feel the vaccine has been a very valuable tool in decreasing the numbers of horses that get West Nile.''

But it's too early to tell if California horses will benefit from the vaccine since West Nile hasn't appeared, health experts said.

That's why some horse trainers, like Josiah at the equestrian center, remain uncertain about inoculating their horses just yet.

``It's not an immediate threat, but certainly we are thinking about doing it,'' Josiah said.

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Photo:

At left, Hannah Cutt, 9, tends to her pony, Jesse James, with vet Susan Bauer at Los Angeles Equestrian Center in Burbank. Morning Mist Farms trainer Missy Sullivan is in the background. Federal approval of a horse vaccine against West Nile virus is expected soon.

Charlotte Schmid-Maybach/Staff Photographer