Piroplasmosis Caught in Australian Quarantine

Detection of a horse positive for piroplasmosis caused significant concern at a Victoria, Australia, Quarantine facility in March. The situation made officials thankful that quarantine surveillance methods were already in place—plans which arose from concerns about seropositive horses which are to compete in the Sydney Olympics this September (see Up Front, March 2000, p. 12).

Piroplasmosis is a blood-borne disease caused by a one-celled protozoan parasite, either Babesia equi or Babesia caballi. The disease primarily is transmitted by ticks, and although it is endemic in many areas of the world, Australia is free of the disease.

The horse was imported March 7, and certification indicated that the horse met all import conditions. The horse had been tested positive for piroplasmosis prior to export, but by error was authorized to travel to Australia. The horse had spent time in South Africa prior to his export from Hong Kong.

"The (positive) horse was a retired racehorse gelding owned by a person in Hong Kong," explained Patricia Ellis, MVSc, who is Principal Veterinary Officer of Horse Industry Programs in Victoria. "The Australian Quarantine and Inspection Service gave the owner of the horse the option of re-export or euthanasia when the blood test results were known. The owner elected not to re-export the horse and the horse was ineligible to return to Hong Kong."

Six horses which were imported with the positive horse were to be kept in isolation for 36 days. All tested negative once, and each must retest negative before release from quarantine.

"Since the incident, Hong Kong has tested its entire horse population for piro, inspected it for ticks, and conducted a tick survey of premises," said Ellis. Results at press time indicated that close to 650 Hong Kong horses (41% of the equine population) tested negative for both B. Equi and B. caballi. No ticks had been found on any horse or on any equine premise or facility.

"The horse was detected in Australia because of a discrepancy between certification and blood test results," said Ellis. "I have no knowledge of how the mix-up occured in Hong Kong."

There will be no changes to Australian policy regarding piroplasmosis because of this incident. Pre-export measures are in place to detect disease and exotic vectors, and there is an established tick-eradication protocol. There are no known suitable vectors native to Australia that have the ability to spread

the disease. Ellis believes that it was fortunate that a piroplasmosis policy was in place, as it provided a quarantine surveillance framework for dealing with the other horses in the same consignment as the infected horse.

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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