Tiny Organism Holds Up Olympic Equine Competition

It took months of negotiations to clear the road to the 1996 Olympic equestrian events in Conyers, Ga.

And all that debate was over an organism too tiny to see that carries a big name -- equine piroplasmosis (Babesiosis) -- and an even bigger "stick."

"Piroplasmosis is a tick-borne disease that causes anemia," said Gary Heusner, a University of Georgia Extension Service animal scientist.

"The organism hasn't been endemic in Georgia," he said, "and that's the problem with allowing infected horses in."

To clear the final hurdle, the Georgia Department of Agriculture reached agreement with the Federation Equestre Internationale (FEI), the governing body of international equestrian competition.

The FEI agreed to follow strict conditions outlined in a 20-point proposal allowing piroplasmosis-positive horses into Georgia for the Games.

The parasite travels through the gut of ticks into the organs, especially the ovaries, where it multiplies and infects the tick's eggs.

The larvae hatch and penetrate the salivary glands, from which they are inoculated into horses.

"Piroplasmosis attacks the red blood cells of the host," Heusner said.

Infected horses become anemic and suffer fever, weight loss, jaundice and, in some cases, death.

"This issue has been a topic of debate and intensive study for over three years when piroplasmosis first became a concern," said Georgia Commissioner of Agriculture Tommy Irvin, "and I feel that more than ample time has been dedicated to the decision on whether or not the positive horses will be allowed to enter the state."

Piroplasmosis was first clinically diagnosed from an imported horse from Cuba, in 1961. The parasite was first spotted in the United States in 1965 in Florida.

"There is one infected horse in Georgia," Heusner said. "He is under strict quarantine."

Piroplasmosis is endemic in Southern Europe, southern Russia, Africa, Asia, the Middle East and Central and South America. The United States, the Netherlands, Ireland, Great Britain and Australia remain free of the parasite.

Piroplasmosis' incubation period is 12 to 30 days for the B. caballi strain and 12 to 15 days for B. equi.

The mortality rate depends on the general immune status of the affected horses and the virulence of the organism. The rate is highest among older horses from piroplasmosis-free areas.

"It's such a big deal because we are a nonendemic area and the mortality rate is higher among horses in nonendemic areas," Heusner said. "Horses in the U.S. are at greater risk of death if horses that test positive are allowed into the country."

Of the two types of piroplasmosis, only B. caballi is easily treated. Treatments include a type of chemotherapy.

Making matters more complicated, the type of tick that transmits piroplasmosis is found in Georgia and is in the feeding season during the months of the Olympics.

As the rules stand, all horses entering the United States must test negative to piroplasmosis, including U.S.-origin horses exported temporarily for competition.

The 20-point proposal put forth by the Department of Agriculture limits the number of positive horses that will be allowed to enter the state; eliminates positive horses from three-day events; and restricts the movement of positive horses once they enter the state.

"Now that a final decision has been made, we must focus all of our energy on the proper implementation of the safeguards outlined in the 20-point proposal," Irvin said.

"It has been and will continue to be my top priority throughout this debate to protect Georgia's and America's horse industry," he said, "and I feel confident that these measures will do just that."

Faith Peppers is the director of public affairs with the University of Georgia College of Agricultural and Environmental Sciences.