Immunoparasitology Laboratory, Faculty of Veterinary Sciences, National University of La Plata, 60 and 118 s/n, 1900 La Plata, Argentina; National Scientific and Technical Research Council (CONICET), Godoy Cruz 2290, C1033AAJ Buenos Aires, Argentina.
Department of Animal Production, Faculty of Agricultural Sciences, National University of Mar del Plata, Balcarce, Argentina.
Vet Parasitol Reg Stud Reports. 2020 Jul;21:100438. doi: 10.1016/j.vprsr.2020.100438. Epub 2020 Jul 22.
Neospora caninum is an important abortifacient agent affecting mainly cattle worldwide. The aim of the present work was to describe the histopathological findings in a naturally infected beef cow and its midterm fetus caused by a genetically defined N. caninum isolate in Argentina. A N. caninum seropositive multiparous Aberdeen Angus pregnant cow and its fetus in the sixth month of gestation were submitted for histopathological, immunohistochemical, serological, and molecular studies and parasite isolation. The cow belonged to a beef herd under extensive management, with a N. caninum seroprevalence of 11%, and low level of annual abortion rate (≤ 5%). The dam had mild lymphocytic infiltrate in CNS, heart and uterus and no parasites were detected by Immunohistochemistry (IHC). No parasitic DNA was detected in the dam's brain, and gamma interferon knockout mice inoculated with brain material did not become infected. Clusters of tachyzoites and parasitic DNA were detected in the placenta by IHC and PCR, respectively. However, isolation from the placenta was unsuccessful. The fetus developed specific antibodies and an inflammatory response was detected in multiple organs. Furthermore, in vitro and in vivo isolation was achieved from gamma interferon knockout mice inoculated with CNS from the fetus. Multilocus-microsatellite typing revealed a genetically defined N. caninum isolate similar to the previously reported as MLG 72. We report the first N. caninum isolate from beef cattle in Argentina.
刚地弓形虫是一种重要的流产病原体，在全球范围内主要影响牛。本研究的目的是描述在阿根廷，一种遗传定义的刚地弓形虫分离株感染自然感染的肉牛及其中期胎儿的组织病理学发现。一头 N. 刚地弓形虫血清阳性的经产阿伯丁安格斯怀孕母牛及其妊娠第六个月的胎儿被提交进行组织病理学、免疫组织化学、血清学和分子研究以及寄生虫分离。该牛属于广泛管理的肉牛群，N. 刚地弓形虫血清阳性率为 11%，年流产率（≤5%）较低。母体的中枢神经系统、心脏和子宫有轻度淋巴细胞浸润，免疫组织化学（IHC）未检测到寄生虫。母体大脑中未检测到寄生虫 DNA，接种脑组织的γ干扰素敲除小鼠未被感染。IHC 和 PCR 分别在胎盘检测到速殖子簇和寄生虫 DNA。然而，从胎盘的分离是不成功的。胎儿发育出特异性抗体，并在多个器官中检测到炎症反应。此外，从接种胎儿中枢神经系统的γ干扰素敲除小鼠中，进行了体外和体内分离。多位点微卫星分型显示，一种遗传定义的刚地弓形虫分离株与先前报道的 MLG 72 相似。我们报告了阿根廷首例来自肉牛的刚地弓形虫分离株。
