September 17, 2004

The West Nile virus has infected its first horse in Stanislaus County and claimed its first life in Northern California with the death of a Tehama County man.
The horse was an 18-year-old female, a Tennessee Fox Trotter from north Modesto, near McHenry Avenue.

Veterinarian Jody Hallstrom said the horse is expected to fully recover, which beats the odds: About 30 percent of infected horses die and another 40 percent show residual symptoms even if they survive the disease.

The Modesto horse had one vaccination before contracting the mosquito-borne virus but had not received its initial booster, part of the two-shot regimen recommended for all horses.

Hallstrom said the horse’s owner noticed drooping and twitching lips last week. Other equine symptoms can include a cocked head, stumbling, an uncoordinated gait or an inability to maintain balance.

The ailing horse was treated with anti-inflammatory drugs. There are no drugs that fight the West Nile infection in humans or horses.

The state is tracking West Nile’s march across California. The disease has been found in 56 of 58 counties.

A Tehama County man’s death was reported Wednesday, the 15th in the state but the first north of San Bernardino County. His age was withheld. Sydnei Wilby, public health director of the Tehama County Health Services Agency, said the victim had symptoms of meningitis and encephalitis and confusion, vomiting and fever.

There have been 14 other virus-related fatalities across Southern California in Los Angeles, Orange, San Bernardino and Riverside counties.

Of 523 human cases in California, 45 had no symptoms and were discovered only through blood screening.

Last week, the state Department of Food and Agriculture confirmed the first equine cases from Lake, Lassen, and Mendocino counties. The yearly total is 301 cases from 26 counties. A total of 115 horses have been euthanized or died after infection.

The local numbers on infected dead birds by county: Merced (1), San Joaquin (23), Stanislaus (30) and Tuolumne (28).

So far among those local counties, only Merced has had a confirmed human case.

Steve Lyle, director of public affairs for California’s Department of Food and Agriculture, encouraged horse owners to vaccinate their animals. “It’s endemic in California now from San Diego to Shasta County,” he said.

Lyle said a new trend may show an increase in peril to the north. “Riverside had been accumulating the most new (equine) cases each week this year and also had the most overall. Last week that changed to Kern and Tehama counties. That indicates a movement of the disease.

“The feeling is we’ll see more movement of the disease, in the sense of a greater number of cases into October,” said Lyle.

He added a caution about next year. “I can’t project with certainty but we are expecting a formidable problem.

“Another thing, in some parts of California, where you don’t have four seasons, there may not be a phase out (of the mosquitoes or infections).”

Local mosquito abatement officials have said they expect fall and winter temperatures around mid-October to put the disease into hibernation.

But David Jones, spokesman for the Stanislaus County Health Services Agency, emphasized that until temperatures drop significantly, it’s still vital for people to take precautions. That’s even more important now that days are getting shorter and more people are being exposed after dark.

Health officials have outlined the most effective ways to guard against contracting West Nile: use a mosquito repellent containing DEET; wear long-legged pants and long-sleeved shirts outdoors; and stay indoors during peak mosquito activity, between dusk and dawn.

Lloyd Douglass, manager of the East Side Abatement District, said fall harvests can make mosquito populations migrate.

“It’s the time of year when chopping corn or shaking the trees takes away their habitat,” explained Douglass. When that happens, he said, the mosquitoes usually go to the nearest houses, usually on the outskirts of urban areas.

If residents notice a sudden increase in mosquitoes, they should call their abatement district.

The Sacramento Bee contributed to this report.

Bee staff writer Roger W. Hoskins can be reached at 578-2311 or at rhoskins@modbee.com.