Therapeutic efficacy of the liposome incorporated buparvaquone on experimental Theileria sergenti infection in calves

리포좀 피포성 buparvaquone의 Theileria sergenti 인공감염 송아지에 대한 치료효과

This study was carried out to completelycure the experimental bovine theileriasis with small unilamella vesicle liposome incorporated buparvaquone which was effective both to schizonts in lymphocyte of lymph nodes and piroplasmic stage in erythrocytes. Small unilamella vesicle liposome incorporated buparvaquone was prepared by French pressure cell method using egg phosphatidylcholine. The diameter of the vesicles was ranged from 5 to 220 nm, but the most vesicles were ranged from 10 to 50 nm in diameter. The incorporation rate for buparvaquone was 100%. Parasitaemia of the 10 calves inoculated with $5{\times}10^8$ erythrocytes infected with Theileria sergenti were first detected from on day 16 to day 23 after inoculation. In calves treated with a dose rate 2.5 mg/kg BW of free buparvaquone, a gradual decrease in piroplasmic parasitaemia was observed following treatment to day 5. However parasitaemia levels returned to near pretreatment values after approximately 60 days. In calves treated with a dose rate 5.0mg/kg BW of free buparvaquone, parasitaemia were disappeared on day 3 after treatment, but there was a mild recrudescence of infection on day 28 after treatment. In calves treated intraavenously with a dose rate 2.5 mg/kg BW of buparvaquone incorporated in liposome, the calves were all cured on day 2 or day 3 after treatment. In calves treated subcutaneously and intraperiotoneally with a dose rate 2.5 mg/kg BW of buparvaquone incorporated in liposome, parasitaemia were disappeared on day 3 or day 4 after treatment, but there was a mild recrudescence of infection on day 40 or day 45 after treatment.