Imidocarb and parvaquone in the treatment of piroplasmosis (Babesia equi) in equids.

The research investigates the effectiveness of two drugs, imidocarb and parvaquone, in treating a parasite infection in horses called piroplasmosis.

Introduction and Objective

The study was conducted to evaluate the efficacy of two drugs, imidocarb and parvaquone, in the treatment of piroplasmosis in equids (horses, ponies, etc.), specifically caused by Babesia equi (a parasite of European origin). The two drugs were tested in horses carrying the infection and in ponies where the infection was acutely induced.

Testing of Imidocarb

• The drug imidocarb, used at a dosage of 4 mg/kg of the equid body weight and given intramuscularly at 72-hour intervals four times, was found to be ineffective in eliminating the Babesia equi-carrier infection in nine mature geldings (castrated male horses).
• In ponies that were acutely infected through splenectomy (removal of the spleen), a single intramuscular administration of 4 mg/kg of imidocarb was also found to be non-therapeutic.

Testing of Parvaquone

• Parvaquone, given at three different dosages and treatment schedules, did not successfully clear the carrier infection either.
• However, there was a noticeable effect when parvaquone was given intramuscularly once at a dosage of 20 mg/kg for acute Babesia equi infections in splenectomized ponies, where parasitemia (the presence of parasites in the blood) started to decrease within 24 hours of the treatment.

Post-treatment Observations

• Despite the apparent early success, the infection was not fully eliminated even after using parvaquone. Within four weeks, the occurrence of secondary parasitemia and anemia was observed.
• Three out of the four ponies treated with parvaquone died from acute piroplasmosis, indicating the treatment’s high mortality rate.

Conclusion

The research provides valuable insights into possible treatments for piroplasmosis but concludes that neither imidocarb nor parvaquone were able to successfully eliminate the Babesia equi infection in the tested scenarios. More research is required to identify a more effective treatment protocol for piroplasmosis in equids.