Highly sensitive and accurate molecular diagnostic methods have not yet been employed for livestock trypanosomosis in the Brazilian Lower Amazon although the first reports of Trypanosoma vivax and Trypanosoma evansi in Brazil were in water buffalo (Bubalus bubalis) in this region. The present study assessed trypanosomosis in buffalo and cattle raised in communal and seasonally flooding pastures in the state of Pará using the fluorescent fragment length barcoding (FFLB) method. T. evansi was not detected, but high infection rates of T. vivax and T. theileri were revealed by a simplified FFLB standardized in the present study that discriminates all trypanosome species infective to livestock in South America. T. vivax infection rates detected by TviCATL-PCR were 24.6% for cattle (n = 61) and 28.1% for buffalo (n = 89). Using the FFLB method, overall T. vivax infection rates increased to 59.6% and 44.3% for buffalo and cattle, respectively. Furthermore, the predominance of a single microsatellite-based genotype of T. vivax was reinforced in the Lower Amazon. Relevant T. vivax infection rates detected in clinically healthy buffalo and cattle through the sampled years (2008–2017) highlight the need for systematic studies to demonstrate the endemic steady state of T. vivax in this region. Our findings provide baseline information for livestock management, including control of T. vivax dispersal, and the introduction of naïve animals. The growing international trade of live livestock from this very important livestock breeding region represents a serious risk for T. vivax spreading outside Amazonia and Brazil.

巴西下亚马逊地区的牲畜锥虫病尚未采用高度灵敏和准确的分子诊断方法，尽管巴西锥虫和伊氏锥虫的首次报道是在该地区的水牛（Bubalus bubalis）中。本研究使用荧光片段长度条形码（FFLB）方法评估了帕拉州公共和季节性洪灾牧场饲养的水牛和牛的锥虫病。未检测到伊万氏锥虫，但间日疟原虫和泰勒虫的感染率很高在本研究中，通过简化的FFLB标准化揭示了这些差异，该差异区分了南美地区所有对牲畜具有感染性的锥虫物种。通过TviCATL-PCR检测到的间日疟原虫感染率为，牛（n  = 61）为24.6 ％，水牛（n  = 89）为28.1％。使用FFLB方法，水牛和牛的总间日疟原虫感染率分别提高到59.6％和44.3％。此外，在下亚马逊地区加强了间日疟原虫基于微卫星基因型的优势。相关间日疟在整个抽样年份（2008-2017年），在临床上健康的水牛和牛中检测到的感染率突出表明，需要系统研究来证明该地区间日疟原虫的流行稳定状态。我们的发现为牲畜管理提供了基线信息，包括对间日疟原虫传播的控制以及幼稚动物的引进。来自这个非常重要的牲畜繁殖地区的活牲畜国际贸易的增长，代表了间日疟原虫传播到亚马逊和巴西以外地区的严重风险。