Faculdade de Ciências Agrárias e Veterinárias - FCAV, Universidade Estadual Paulista - UNESP, Jaboticabal, SP, Brasil.
Departamento de Medicina Veterinária, Universidade de Vila Velha - UVV, Vila Velha, ES, Brasil.
Rev Bras Parasitol Vet. 2021 Apr 26;30(1):e020220. doi: 10.1590/S1984-29612021019. eCollection 2021.
Trypanosoma vivax infections cause nonspecific clinical signs in cattle associated with aparasitemic intervals, making disease diagnosis a challenge. In Brazil, diminazene aceturate and isometamidium chloride (ISM) are available to treat bovine trypanosomosis. The objective of this study was to follow-up, by molecular and serological techniques, dairy cattle naturally infected by T. vivax after ISM treatment. Thirty cattle naturally infected with T. vivax received two applications of ISM, at a dosage of 1.0 mg/kg intramuscularly, on days 0 and 150. For T. vivax diagnosis, EDTA-blood and serum samples were evaluated on 0, 7, 15, 30, 60, 90, 120, 150, 180, 210, and 240 days after treatment PCR, Loop-mediated isothermal amplification (LAMP) and ELISA. Animals with persistent detection of T. vivax DNA by both PCR and LAMP were found and continuous detection of anti-T. vivax IgG antibodies by ELISA, suggesting the presence of T. vivax resistance to ISM. The combination of LAMP and ELISA tests can prevent misdiagnosis of the parasite clearance in treated cattle, contributing to better disease control. This is the first experiment that demonstrates the persistence infection of T. vivax under ISM treatment in a natural infected herd and evidence of ISM chemotherapy-resistant T. vivax in Brazil.
布氏锥虫感染引起牛的非特异性临床症状，与无寄生虫血症间隔有关，使疾病诊断具有挑战性。在巴西，可用乙酰胂胺和米替米星（ISM）治疗牛锥虫病。本研究的目的是通过分子和血清学技术对自然感染 T. vivax 的奶牛进行随访，这些奶牛在接受 ISM 治疗后。30 头自然感染 T. vivax 的奶牛接受了两次 ISM 治疗，剂量为 1.0mg/kg 肌肉注射，第 0 天和第 150 天。为了诊断 T. vivax，在治疗后第 0、7、15、30、60、90、120、150、180、210 和 240 天，使用 EDTA 血液和血清样本进行 PCR、环介导等温扩增（LAMP）和 ELISA。发现了通过 PCR 和 LAMP 均持续检测到 T. vivax DNA 的动物，并且通过 ELISA 持续检测到抗 T. vivax IgG 抗体，表明 T. vivax 对 ISM 存在耐药性。LAMP 和 ELISA 联合检测可防止治疗牛寄生虫清除的误诊，有助于更好地控制疾病。这是第一个证明在自然感染群中 ISM 治疗下 T. vivax 持续感染的实验，并证明了巴西存在 ISM 化疗耐药的 T. vivax。
