Departamento de Patologia e Clínicas, Universidade Federal da Bahia, Escola de Medicina Veterinária, Avenida Ademar de Barros 500, Ondina, Salvador, Bahia 40170-110, Brazil.
Parasitol Res. 2010 Jan;106(2):457-61. doi: 10.1007/s00436-009-1686-4. Epub 2009 Nov 27.
Neospora caninum, Hammondia sp., and Toxoplasma gondii are parasites with morphological and genetic similarities. N. caninum and T. gondii are important abortive agents of cattle and sheep, respectively, and may infect numerous animal species. Hammondia sp. is not known to induce disease in animals, but may cause confusion in the identification of closely related coccidia. The aim of this study was to investigate infection rates caused by N. caninum, Hammondia sp., and T. gondii in beef cattle using a nested PCR for Toxoplasmatinae rDNA, followed by sequencing of the PCR products. Antibodies to N. caninum and T. gondii were also investigated in the tested animals. Brains and hearts were obtained from 100 beef cattle in a slaughterhouse in Bahia. Seven samples from brain tested positive for Toxoplasmatinae DNA. No positive reactions were found in heart tissues. After sequencing of the PCR products from all positive tissues, five sequences matched with N. caninum and two matched with T. gondii. Antibodies to N. caninum and T. gondii were found in 20% and 26% of the animals, respectively. The confirmation of N. caninum and the absence of Hammondia heydorni in the tested animals is suggestive that cattle are not efficient intermediate hosts of H. heydorni; however further studies need to be performed using a greater variety of tissues and a higher sample size. The detection of T. gondii DNA in bovine tissues reinforces the potential risk of transmission of this parasite to humans and other animals through the consumption of bovine meat.
刚地弓形虫、哈氏巴贝斯虫和新孢子虫在形态和遗传上具有相似性,都是寄生虫。犬新孢子虫和刚地弓形虫分别是牛和羊的重要流产病原体,可能感染许多动物物种。哈氏巴贝斯虫目前已知不会在动物中引起疾病,但可能会导致对密切相关球虫的鉴定产生混淆。本研究旨在使用巢式 PCR 检测 Toxoplasmatinae rDNA,然后对 PCR 产物进行测序,调查牛感染犬新孢子虫、哈氏巴贝斯虫和刚地弓形虫的感染率。还调查了检测动物的抗犬新孢子虫和刚地弓形虫抗体。从巴伊亚州一家屠宰场的 100 头肉牛中获得了大脑和心脏。7 份脑组织样本的 Toxoplasmatinae DNA 检测呈阳性,心脏组织未发现阳性反应。对所有阳性组织的 PCR 产物进行测序后,有 5 个序列与犬新孢子虫匹配,2 个序列与刚地弓形虫匹配。20%的动物检测出抗犬新孢子虫抗体,26%的动物检测出抗刚地弓形虫抗体。未在检测动物中发现哈氏巴贝斯虫,这表明牛不是哈氏巴贝斯虫的有效中间宿主;然而,需要使用更多种类的组织和更大的样本量进行进一步研究。牛组织中刚地弓形虫 DNA 的检测,加强了通过食用牛肉传播这种寄生虫给人类和其他动物的潜在风险。