OIE Reference Laboratory for Surra, OIE Collaborating Center, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
National Institute for Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Viet Nam.
Vet Parasitol. 2014 Mar 17;201(1-2):18-23. doi: 10.1016/j.vetpar.2014.01.009. Epub 2014 Jan 27.
Trypanosoma evansi infection, or surra, is currently affecting various species of animals, especially water buffaloes. Since diagnosis is an important aspect of surra control, development of novel diagnostic antigens is of interest to implement and improve the currently utilized methods. Our study evaluated the tandem repeat antigen TeGM6-4r in T. evansi antibody detection in water buffaloes. TeGM6-4r-based ELISA was performed with 20 positive and 8 negative controls and 484 field samples from water buffaloes in Northern Vietnam. To examine cross-reactivity, sera from Japanese cattle that had been experimentally infected with Theileria orientalis (n=10), Babesia bovis (n=3), Babesia bigemina (n=7) and Trypanosoma theileri (n=59) were included in the study. The sensitivity of the test was 80%. TeGM6-4r did not react with Theileria or Babesia infected sera, however it showed cross reactivity with 11/59 T. theileri infected samples. The reference test, CATT/T. evansi also reacted with 3/59 T. theileri infected sera. The lysate antigen-based ELISA reacted with 4/59 T. theileri, 9/10 Theileria and 3/10 Babesia infected sera. In contrast, TeGM6-4r-based ELISA was 86.3% sensitive and 58.3% specific in the screening of field samples. The average seroprevalence of T. evansi infection among water buffaloes in Northern Vietnam was 27.1% by CATT/T. evansi and 53.7% by TeGM6-4r. Seroprevalence in the five surveyed provinces ranged from 17.4% to 39.8% in the reference test, and 47.3% to 67.3% in the recombinant antigen based test. The finding indicated that the disease is still widely endemic in the area and that surveillance programs need to be carried out regularly to better control surra. We proposed TeGM6-4r as a useful serodiagnostic antigen for the detection and epidemiological surveillance of T. evansi infection among water buffaloes.
伊氏锥虫感染，又称苏拉病，目前正在影响多种动物物种，尤其是水牛。由于诊断是苏拉病控制的重要方面，因此开发新型诊断抗原对于实施和改进目前使用的方法具有重要意义。本研究评估了伊氏锥虫抗体检测中的串联重复抗原 TeGM6-4r 在水牛中的应用。使用 20 个阳性和 8 个阴性对照以及来自越南北部的 484 份水牛现场样本进行了基于 TeGM6-4r 的 ELISA 检测。为了检查交叉反应性，研究中包括了来自日本牛的血清，这些牛已被实验感染东方泰勒虫（n=10）、牛巴贝斯虫（n=3）、双芽巴贝斯虫（n=7）和无浆体（n=59）。该测试的灵敏度为 80%。TeGM6-4r 与感染东方泰勒虫或巴贝斯虫的血清不反应，但与 11/59 份无浆体感染样本发生交叉反应。参考测试 CATT/T. evansi 也与 3/59 份无浆体感染血清反应。基于裂解物抗原的 ELISA 与 4/59 份无浆体、9/10 份东方泰勒虫和 3/10 份巴贝斯虫感染血清反应。相比之下，TeGM6-4r 基于 ELISA 在筛选现场样本时的灵敏度为 86.3%，特异性为 58.3%。越南北部水牛中伊氏锥虫感染的平均血清阳性率为 CATT/T. evansi 的 27.1%和 TeGM6-4r 的 53.7%。五个调查省份的血清阳性率在参考测试中为 17.4%至 39.8%，在重组抗原测试中为 47.3%至 67.3%。这一发现表明，该疾病在该地区仍然广泛流行，需要定期开展监测计划，以更好地控制苏拉病。我们提出 TeGM6-4r 作为一种有用的血清诊断抗原，用于检测和监测水牛中的伊氏锥虫感染。
