Department of Epidemiology and Public Health, Federal Rural University of Rio de Janeiro, BR 465, Km 7, Seropédica, RJ 23890000, Brazil.
Department of Parasitology, Federal Rural University of Rio de Janeiro (UFRRJ), BR 465, Km 7, Seropédica, RJ 23890000, Brazil.
Vet Parasitol Reg Stud Reports. 2020 Dec;22:100466. doi: 10.1016/j.vprsr.2020.100466. Epub 2020 Sep 14.
In Brazil, infection in cattle was first reported in the state of Pará, in 1944, and the presence of the parasite has already been recorded in several states. The purpose of this study was to report the clinical-pathological aspects of a natural infection by T. vivax in dairy cattle in the state of Rio de Janeiro. Twelve outbreaks of the infection were diagnosed in 11 municipalities from April 2016 to October 2018. All properties had acquired cattle from states where the disease had already been recorded and it was found that needles for oxytocin administration had been shared. These outbreaks were studied by visiting the properties to perform anamnesis, clinical exams and collection of material for laboratory diagnosis. Laboratory diagnosis was performed through parasitological, molecular and histopathological techniques. Animals with confirmed diagnosis for T. vivax showed anemia, lack of appetite, decreased milk production, weight loss, weakness, abortion, diarrhea and neurological signs. The main histological lesions found were meningoencephalitis and lymphohistiocytic myocarditis. In the central nervous system, the lesions were more severe in the brain compared to the spinal cord, being progressively more severe in the rostro-dorsal direction. Also, they were more accentuated in the white matter compared to the gray matter. Due to nonspecific clinical signs, laboratory tests were key for diagnosis. Trypanosomiasis in cattle herds in the state of Rio de Janeiro, Brazil, is of great concern because of its potential to cause economic losses.
在巴西，1944 年首次在帕拉州报告了牛感染病例，此后该寄生虫已在多个州被发现。本研究旨在报告里约热内卢州奶牛自然感染锥虫的临床病理方面。2016 年 4 月至 2018 年 10 月，11 个城市诊断出 12 起感染爆发。所有农场都从已经记录到该疾病的州引进了牛，并发现了催产素注射针共享的情况。通过访问农场进行病史调查、临床检查和实验室诊断材料收集，对这些爆发进行了研究。实验室诊断采用寄生虫学、分子和组织病理学技术进行。确诊为锥虫的动物表现出贫血、食欲不振、产奶量减少、体重减轻、虚弱、流产、腹泻和神经症状。发现的主要组织学病变为脑膜脑炎和淋巴组织细胞性心肌炎。在中枢神经系统中，与脊髓相比，大脑中的病变更为严重，并且在头侧-尾侧方向上逐渐加重。与灰质相比，白质中的病变更为明显。由于临床症状不具特异性，实验室检查对诊断至关重要。巴西里约热内卢州牛群锥虫病令人担忧，因为它可能导致经济损失。
