Barr B C, Anderson M L, Dubey J P, Conrad P A
California Veterinary Diagnostic Laboratory System, Davis.
Vet Pathol. 1991 Mar;28(2):110-6. doi: 10.1177/030098589102800202.
Eighty bovine fetuses with presumed protozoal infections from a previous 2-year retrospective study were examined by immunohistochemistry using antisera against Neospora caninum. In 66 (83%) of the fetuses, protozoa were found that reacted positively with anti-N. caninum sera. In three (4%) additional fetuses, protozoa identified as Sarcocystis species did not react, and in two fetuses (3%) single protozoal clusters were found only in hematoxylin and eosin-stained slides. A group of 20 fetuses were chosen for further evaluation. They included 14 fetuses from the first group of 80 fetuses plus six additional fetuses that had large numbers of protozoa in the fetal brain. The 20 fetuses were examined immunohistochemically with antisera to N. caninum, Hammondia hammondi, and Toxoplasma gondii. Protozoa from 3/20 fetuses, identified as Sarcocystis species, failed to react with any antisera. In 16/20 fetuses protozoa reacted positively to antisera against N. caninum, and in most cases reacted to H. hammondi, and weakly to one or more of the antisera against T. gondii. Thick-walled protozoal tissue cysts were found in the brain of four of these 16 fetuses by transmission electron microscopy. The cyst wall morphology was comparable to N. caninum. The results suggested that a single protozoal parasite of unknown identity was responsible for most of the bovine abortions. By immunohistochemistry, the unknown protozoon reacted most strongly and consistently to N. caninum antisera, but was antigenically distinct from N. caninum. Ultrastructurally, tissue cysts found in four fetuses most closely resembled Neospora caninum.
在一项为期两年的回顾性研究中，对80例疑似原生动物感染的牛胎儿进行了免疫组织化学检查，使用抗犬新孢子虫抗血清。在66例（83%）胎儿中，发现原生动物与抗犬新孢子虫血清呈阳性反应。另外3例（4%）胎儿中，鉴定为肉孢子虫属的原生动物无反应，2例（3%）胎儿仅在苏木精和伊红染色切片中发现单个原生动物簇。选择一组20例胎儿进行进一步评估。其中包括第一组80例胎儿中的14例，以及另外6例胎儿脑内有大量原生动物的胎儿。对这20例胎儿用抗犬新孢子虫、哈蒙德新孢子虫和刚地弓形虫抗血清进行免疫组织化学检查。20例胎儿中有3例的原生动物鉴定为肉孢子虫属物种，未与任何抗血清发生反应。20例胎儿中有16例的原生动物对抗犬新孢子虫抗血清呈阳性反应，大多数情况下对哈蒙德新孢子虫抗血清有反应，对一种或多种抗刚地弓形虫抗血清反应较弱。通过透射电子显微镜在这16例胎儿中的4例脑内发现了厚壁原生动物组织囊肿。囊肿壁形态与犬新孢子虫相似。结果表明，一种身份不明的单一原生动物寄生虫是导致大多数牛流产的原因。通过免疫组织化学，这种身份不明的原生动物对犬新孢子虫抗血清反应最强且最一致，但在抗原性上与犬新孢子虫不同。在超微结构上，4例胎儿中发现的组织囊肿与犬新孢子虫最为相似。
