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Abstract：
Leptospirosis is an infectious disease that affects domestic animals, wild animals, and humans. It represents a public health problem and has an important economic impact on livestock. This study aims to investigate the importance of genital and transplacental infection in the epidemiology of leptospirosis in cows maintained in Caatinga biome conditions, Northeastern Brazil, as well as reporting organs colonized by Leptospira spp. in embryos and fetuses. Blood, urinary tract (urine, bladder, and kidney), and reproductive tract (vaginal fluid, uterus, uterine tube, ovary, and placenta) samples were collected from 15 slaughtered pregnant cows. Two embryos and 13 fetuses were sampled. Central nervous system and choroid ovoid samples were collected from embryos. Blood, central nervous system, lung, peritoneal liquid, abomasal content, liver, spleen, urine, bladder, kidney, and reproductive system samples were collected from fetuses. Diagnostic methods included the microscopic agglutination test (MAT) using a collection of 24 serovars belonging to 17 different pathogenic serogroups of five species as antigens, as well as polymerase chain reaction (PCR). Anti-Leptospira spp. antibodies were found in 9 cows (60%), while 13 cows (86.67%) had at least one organ or urine with leptospiral DNA. No fetus was seroreactive. Among the embryos and fetuses, 13 (86.67%) presented leptospiral DNA, proving a high frequency of transplacental infection (100%). For cows, the most frequent biological materials regarding Leptospira spp. DNA detection were placenta (13 out of 15 samples; 86.7%), uterus (10 out of 15 samples; 66.7%), and vaginal fluid (5 out of 15 samples; 33.3%), while, for fetuses/embryos, the most frequent PCR-positive samples were choroid ovoid (1/2; 50%), spleen (6/13; 46.2%), kidney (5/13; 38.5%), and central nervous system (5/15; 33.3%). Sequenced samples based on the LipL32 gene presented 99% similarity with L. borgpetersenii. The results indicate that transplacental infection is an efficient way of spreading Leptospira spp. in cows maintained in Caatinga biome conditions. Therefore, prevention and control strategies must include actions that interrupt transmission through this alternative route.
摘要：
钩端螺旋体病是一种影响家畜的传染病,野生动物,和人类。它代表了公共卫生问题，对牲畜具有重要的经济影响。本研究旨在调查在Caatinga生物群落条件下维持的奶牛钩端螺旋体病流行病学中生殖器和经胎盘感染的重要性。巴西东北部,以及报告被钩端螺旋体定植的器官。胚胎和胎儿。血，泌尿道（尿液，膀胱,和肾脏)，和生殖道(阴道液，子宫,子宫管,子房,和胎盘）样品是从15头屠宰的怀孕母牛中收集的。对两个胚胎和13个胎儿进行取样。从胚胎中收集中枢神经系统和脉络膜卵形样品。血，中枢神经系统,肺，腹膜液,恶臭含量，肝脏,脾,脾尿液,膀胱,肾,生殖系统样本是从胎儿收集的。诊断方法包括显微镜凝集试验（MAT），使用属于5种物种的17种不同致病性血清群的24种血清变型作为抗原，以及聚合酶链反应（PCR）。抗钩端螺旋体。在9头奶牛(60%)中发现了抗体，而13头母牛（86.67％）至少有一个器官或尿液具有钩端螺旋DNA。没有胎儿呈血清反应性。在胚胎和胎儿中，13（86.67%）呈现钩端螺旋体DNA，证明胎盘感染的频率很高（100％）。对于奶牛来说,关于钩端螺旋体属的最常见的生物材料。DNA检测为胎盘（15个样本中有13个；86.7%），子宫（15个样本中有10个；66.7%），和阴道液（15个样本中的5个；33.3％），while,对于胎儿/胚胎，最常见的PCR阳性样品是脉络膜卵圆形（1/2；50％），脾脏（6/13；46.2％），肾脏（5/13;38.5％），中枢神经系统（5/15；33.3％）。基于LipL32基因的测序样品与博氏乳杆菌具有99％的相似性。结果表明，经胎盘感染是传播钩端螺旋体的有效方法。在卡廷加生物群落条件下维持的奶牛中。因此,预防和控制策略必须包括通过这种替代路线中断传播的行动。
