A South Texas ranch is the epicenter of a months-long outbreak of a deadly horse disease rarely seen in the United States that kills as many as 20 percent that it infects.
As of Jan. 20, 364 cases of equine piroplasmosis had been confirmed. Of those, 289 are on the sprawling King Ranch. The rest are scattered across Indiana, Texas, Alabama, California, Florida, Louisiana, Minnesota, North Carolina, New Jersey, Tennessee, Utah and Wisconsin, according to the World Animal Health Information System.
A South Texas ranch, identified by the Texas Animal Health Commission as the outbreak’s source, has sold horses with equine piroplasmosis in 15 states since 2004.
Jack Hunt, King Ranch CEO, confirmed that the outbreak started on the ranch.
Horses, donkeys, mules and zebras are susceptible to the disease, which is caused by two parasitic organisms. More severely affected animals can have fever, anemia, jaundiced mucous membranes, swollen abdomens and labored breathing.
"It will kill a horse," said Mike Vickers, a Brooks County veterinarian and commissioner on the Texas Animal Health Commission. "It’s very, very serious."
No horses have died, officials believe. The ranch’s 300-plus horses have since been quarantined.
Piroplasmosis had never been seen in Texas and rarely had been found in the United States, according to the Texas Animal Health Commission, the state’s livestock and poultry health regulatory agency. It is prevalent in 90 percent of the world and commonly found in Mexico.
Once a horse is infected, the parasitic organisms remain in the horse’s system permanently, making the horse a potential carrier. It does not affect humans or other non-equine mammals.
Ticks usually transmit the disease to horses, but it also has been spread from animal to animal by contaminated needle. There is some concern that it might be spread by horsefly bites, Vickers said.
Hunt, who has been in the ranching business for 35 years, said he had never heard of the disease when it was discovered in October.
Eight other ranches in Jim Wells, Kleberg and Brook counties have been quarantined and tied to the initial outbreak, said James Lenarduzzi, a veterinarian with the Texas Animal Health Commission. Horses from ranches adjacent to King Ranch will be tested in coming weeks to determine if they are infected.
The 825,000-acre King Ranch includes most of Kleberg and Kenedy counties and portions of Brooks, Jim Wells, Nueces and Willacy counties. It is renowned for its horses, including 1946 Triple Crown winner Assault and 1950 Kentucky Derby and Belmont Stakes winner Middleground.
Though the ranch still has a horse-breeding program, no horses have been sold since the quarantine, Hunt said.
The Texas Animal Health Commission issued its first directive on the South Texas-based infection Oct. 20, noting that the disease had been confirmed on an undisclosed ranch. Canada promptly banned imports of Texas horses, though later relaxed the restrictions. Ten states have stringent restrictions in place that call for testing and other controls before a horse can be imported from Texas.
State Rep. Yvonne Gonzalez Toureilles, D-Alice, who chairs the House Committee for Agriculture and Livestock, got involved after several South Texas ranchers complained that King Ranch has kept its name away from the outbreak, which started in October.
Hunt said King Ranch self-reported the infection, which was required by law, and has worked openly with state and federal agencies since.
The state has 1 million horses. Owners, family members and volunteers spend $3 billion per year attending competitive events with more than 250,000 horses, according to a Texas A&M University report. And horse owners have more than $13 billion invested in barns, towing vehicles, trailers, tack and related equipment and spend more than $2.1 billion annually to maintain their horses.
Some South Texas ranchers are angry that the state and federal governments have been tightlipped on the disease’s origin, said Lavoyger Durham, who manages the 13,000-acre El Tule Ranch near Falfurrias for Brown & Root heiress Nancy Brown Negley.
King Ranch also is working with the U.S. Department of Agriculture and some of the nation’s top epidemiologists on experimental procedures to remove the parasite from a horse’s system, Hunt said.
"They have sent great people to work on this project, and we have had lots of interaction," Hunt said. "It’s just a process we are all going to have to go through. It’s not pleasant for anybody affected by it."
