Washington, April 21 (Inditop) An official investigation has opened into the mysterious deaths of at least 21 horses in the US, the US Polo Association said Monday.

The animals died just hours before a quarter-final match Sunday at the 105th US Open Polo Championship in Wellington, Florida. The tournament concludes South Florida’s winter polo season.

The horses were from the Lechuza Caracas team of Venezuela, which has been playing annually in the event since 1999. Team owner Victor Vargas, a Venezuelan multimillionaire, was “in seclusion,” according to Peter Rizzo, United States Polo Association (USPA) executive director.

“This is a very, very traumatic time for him,” Rizzo told DPA.

The investigation is being carried out by the Florida State Department of Agriculture, which is conducting post-mortem examinations and toxicology testing on the remains. Results are expected by week’s end, Rizzo said.

Seeking to dampen wild rumours circulating about the cause, Paul Wollenman, a veterinarian who led the effort to rescue the horses as they started to collapse Sunday, said: “Based on initial, overwhelming clinical evidence, this medical event was isolated to the Lechuza barn and horses, and the initial evidence shows no infectious element.”

The polo horses on the Lechuza Caracas team ranged in age from five to 15 years and came mainly from US and Argentine breeders, Rizzo said.

The winner of Sunday’s quarter-final at the International Polo Club Palm Beach would have advanced to the semi-finals in the year’s culminating tournament. The Lechuza Caracas horses were “the best of the best,” Rizzo said.

After the tournament, many of them would have been turned out to rest until the next season, he said.

Rizzo, a second-generation polo player, said it takes at least two years to train horses for the sport. The financial loss was estimated by the Palm Beach Daily News at more than $1.5 million.

Rizzo said he had never heard or seen of such a tragedy in polo history: “It’s unbelievably sad, … so unreal. … You can’t get your arms around it.”

Right before the 3 pm match, as the Lechuza Caracas trainers were preparing their horses, two horses collapsed and several others began exhibiting dizziness and disorientation, according to a statement by the North American Polo League.

Veterinarians “rushed to the scene” and began treating the symptoms, the league said.