Outbreak of horse ailment uncommon to U.S. traced to famous ranch in Texas

A famous South Texas ranch is the epicenter of a deadly horse disease with a 20 percent mortality rate. Through Jan. 20, "364 cases of equine piroplasmosis had been confirmed," Jaime Powell of the Scripps Howard News Service reports. "Of those, 289 are on the sprawling King Ranch." The World Animal Health Information System also reports cases in Indiana, Texas, Alabama, California, Florida, Louisiana, Minnesota, North Carolina, New Jersey, Tennessee, Utah and Wisconsin.

The Texas Animal Health Commission has identified the King Ranch, right, between Corpus Christi and Brownsville, as the source of the outbreak. The ranch has sold horses with equine piroplasmosis in 15 states since 2004. "Horses, donkeys, mules and zebras are susceptible to the disease, which is caused by two parasitic organisms," Powell writes. "More severely affected animals can have fever, anemia, jaundiced mucous membranes, swollen abdomens and labored breathing." (King Ranch map)

While the disease has a high mortality rate, no horses in Texas have died yet and the ranch's 300-plus horses have been quarantined. The case marks the first occurrence of piroplasmosis in Texas, Powell reports. The disease rarely appears in the U.S., but it is prevalent in 90 percent of the world and commonly found in Mexico. 1946 Triple Crown winner Assault and 1950 Kentucky Derby and Belmont Stakes winner Middleground were bred at the 825,000-acre King Ranch. (Read more)