Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA.
Department of Animal Medicine, Faculty of Veterinary Medicine, University of Alexandria, Alexandria, Egypt.
Parasit Vectors. 2024 Aug 12;17(1):337. doi: 10.1186/s13071-024-06397-0.
Theileria haneyi is one of the three known causative agents of equine piroplasmosis. While imidocarb is generally effective in the clearance of the highly pathogenic Theileria equi, it is ineffective in the treatment of T. haneyi. Moreover, co-infection with T. haneyi has been shown to impede the successful treatment of T. equi. Furthermore, tulathromycin and diclazuril have demonstrated inefficacy in eradicating T. haneyi. The absence of an effective therapeutic agent against this parasite represents a significant obstacle in managing equine piroplasmosis.
To address this issue, we evaluated the efficacy of buparvaquone in the treatment of T. haneyi in chronically infected horses.
Our findings showed that treatment of horses with the recommended dose of 2.5 mg/kg of buparvaquone led to a rapid abatement of T. haneyi levels, to a level where the parasites were not detectable by nested PCR. Following treatment, the horses remained PCR negative for a minimum of seven weeks until recrudescence occurred. Subsequent re-administration of buparvaquone at an increased dosage of 6 mg/kg upon recrudescence failed to exert a theilericidal effect on T. haneyi. Throughout the treatment regimen, the hematological parameters of the horses and most components of the chemistry panel remained within the normal range, except for blood urea nitrogen levels, which fell below the normal range in certain instances.
BPQ at 2.5 mg/kg and 6 mg/kg had a robust theilericidal effect but was ineffective in the clearance of the T. haneyi infection in persistently infected animals.
泰勒虫（Theileria haneyi）是引起马梨形虫病的三种已知病原体之一。虽然咪唑苯脲通常可有效清除高度致病的马媾疫锥虫，但对泰勒虫（Theileria haneyi）无效。此外，泰勒虫（Theileria haneyi）的合并感染已被证明会阻碍马媾疫锥虫的成功治疗。此外，大环内酯类药物（tulathromycin）和二氯苯胍（diclazuril）已被证明无法根除泰勒虫（Theileria haneyi）。针对这种寄生虫缺乏有效的治疗药物，这是马梨形虫病管理的一个重大障碍。
为了解决这个问题，我们评估了双羟萘酸噻嘧啶（buparvaquone）在治疗慢性感染马泰勒虫（T. haneyi）中的疗效。
我们的研究结果表明，用推荐剂量的 2.5 毫克/千克的双羟萘酸噻嘧啶（buparvaquone）治疗马可迅速降低泰勒虫（T. haneyi）的水平，使寄生虫通过巢式 PCR 检测不到。治疗后，马在至少七周内 PCR 检测结果均为阴性，直到复发。复发时增加剂量至 6 毫克/千克再次给予双羟萘酸噻嘧啶（buparvaquone）未能对泰勒虫（T. haneyi）产生杀原虫作用。在整个治疗方案中，马的血液学参数和大多数化学指标的大部分成分均在正常范围内，除了血尿素氮水平在某些情况下低于正常范围。
2.5 毫克/千克和 6 毫克/千克的 BPQ 对泰勒虫（T. haneyi）具有强大的杀原虫作用，但对持续感染动物的泰勒虫（T. haneyi）感染清除无效。
