WEST NILE VIRUS THREATENS HORSES.

Byline: Eugene Tong Staff Writer

CASTAIC - The recent discovery of three horses infected with West Nile virus in the community of Piru - just 12 miles west of the Santa Clarita Valley in Ventura County - has put local equestrians like Kathy Potts on alert.

``That's real close - just a couple of crow-flies over the hill,'' said Potts, owner of Back Achers Ranch, a Castaic boarding facility for some 45 quarter horse, Arabian and other breeds. ``As horse owners, you just have to deal with it. It's just another thing to worry about.''

Though there have been no reports of horses infected with the mosquito- borne virus in Los Angeles County, five cases have been tallied in bordering communities in Ventura County. One horse in Piru died.

Robert Ragsdale, a large-animal veterinarian for 33 years with a practice in Saugus, said it was only a matter of time before livestock are infected.

``There's more prevalence of the West Nile virus mosquitoes in the area, so you're going to have some spillover into the livestock,'' he said. ``It's here to stay, I'm sure.''

The virus, which can lead to complications such as encephalitis (inflammation of the brain) and meningitis, is transmitted by mosquitoes. Humans - and horses - cannot catch the disease from each other.

Since February 2005, 10 birds in the Santa Clarita area have tested positive for the disease, and mosquito carriers were found in Valencia neighborhoods earlier this month.

Last year, three horses in Ventura County died from West Nile. In Los Angeles County, 16 horses were infected, with eight deaths. Statewide, 540 horses were infected.

This year, 277 horses statewide have been diagnosed with the virus, and 120 have died or were euthanized, according to the state Department of Health Services. Out of 370 human cases reported statewide this year, eight people have died from the disease.

``We'll probably have a few more cases than we had last year,'' Ragsdale said. ``This will be the highest, and then in a few years it'll fall back again.''

Ventura County officials warned residents last week to keep ponds drained and introduce mosquito fish to water troughs - both prime mosquito breeding grounds on ranches.

``We've gone out and surveyed all our known mosquito sources in the area,'' said William Stratton, a Ventura County environmental health division manager. ``When we find any mosquitoes breeding, we control it.''

``You just don't have a lot of standing water to attract the mosquitoes,'' said Potts, owner of her ranch since 1997. ``The county brought us out some mosquito-(eating) fish - our horse water troughs have them.''

As with people, older horses, donkeys and mules with weakened immune systems are more at risk - it's usually fatal for about one-third of infected horses, Ragsdale said.

``(The symptoms) are neurological signs - they look like the other encephalitis - trembling, incoordination, stumbling,'' he said.

Horses can be vaccinated against the virus - shots are administered every six months to a year at roughly $25-$35 per treatment.

``Controlling mosquitoes and vaccination is the big thing,'' Ragsdale said. ``It's been going on for 3-4 years now. Most people have been vaccinated. Owner compliance has been pretty high.''

``It's a small price to pay to keep them healthy,'' said Roberta Monroe, 57, of Castaic, who keeps two horses at a Sloan Canyon ranch. ``It's the most important thing you do. She keeps me safe on the trails. It's my job to keep her safe.''

Christine Coey, 58, of Castaic, looking after her 13-year-old quarter horse, said it's just like caring for any other pet.

``It's like having a dog - you worry about rabies,'' she said. ``There's that joke if you own a horse: driver carries no cash.''

Eugene Tong, [phone]

eugene.tong(at)dailynews.com

CAPTION(S):

2 photos

Photo:

(1) Veterinarian Robert Ragsdale says it is only a matter of time before livestock are infected with the West Nile virus.

(2) Roberta Monroe says vaccinating her horses against the West Nile virus is ``a small price to pay to keep them healthy.''

Hans Gutknecht/Staff Photographer