4 More Horses Stricken by Mystery Illness

Four more horses at the Orange County Fairgrounds Equestrian Center became ill late Saturday night and on Sunday afternoon, but no more have died of the mysterious malady, a fairgrounds official said Sunday.

Four horses have died since Oct. 28 of a strange ailment whose cause veterinarians have been unable to identify. The latest death was early Saturday morning. The new outbreak brings to 12 the number of horses at the center to have contracted the illness.

“No more horses have died since Saturday, but we have four more horses that have come down with this,” Pamela Gimble, manager of the center, said Sunday. “Three more horses came down sick Saturday night, and one this afternoon.”

The center boards 260 privately owned horses. A quarantine has been in effect at the center since Friday.

The center had two veterinarians “from UC Davis here today, but we still don’t know what’s causing this,” Gimble said Sunday. “Everything is just speculation at this point.”

She said that a specialist from the state toxicological laboratory in San Bernardino also visited the center on Sunday.

In addition, three local veterinarians have been examining the sick horses, Gimble said.

But, she said, none of the experts so far could say conclusively what is causing the illness.

Gimble said the first symptoms are shaking knees and quivering muscles. Then, she said, the horses “go down and they’re not able to get back up again; it’s as if they’re unable to use their hips.”

“They start breathing heavier than normal,” she said, but strangely enough, their body temperatures remain normal, and it appears that their sleeping patterns also stay normal.

“Another strange thing is that the horses that are sick will continue to eat normally right up until the time they die,” she said. Curiously, though, “they all have become sick in either the afternoon or night,” she said.

The equestrian center changed the feed it was giving horses, Gimble said. Tests on the previous feed have not yet turned up anything conclusive, Gimble said.