Experimental infection of non-pregnant and pregnant sheep with Neospora caninum
Experimental infection of non-pregnant and pregnant sheep with Neospora caninum
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DOI：
10.1016/s0021-9975(97)80062-x
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发表时间：
1997-07-01
影响因子：
0.8
通讯作者：
Innes, EA
中科院分区：
文献类型：
--
作者：
Buxton, D;Maley, SW;Innes, EA
在最初的实验中，将 21 只羊分成 5 或 6 只一组，皮下 (sc) 接种 10(8)、10(6) 或 10(4) 犬新孢子虫速殖子（利物浦分离株）或对照接种物，并监测临床症状和“血清转化”。给予两种较高剂量的动物表现出发热反应，并且接种寄生虫的所有三组动物均表现出血清转化。在第二个实验中，12只怀孕的绵羊在妊娠90天时每只皮下接种10(6)速殖子，并在接种后25、40和53天(dpi)处死四只羊，以检查胎儿和胎盘。研究中包括适当的对照母羊。所有胎儿在被杀死前都还活着，只有一个胎儿除外，该胎儿在 40 dpi 下被发现已被木乃伊化。在胎儿中枢神经系统（CNS）和胎盘组织中均发现一致的组织病理学病变。在后者中，局灶性坏死在 25 dpi 时较轻微，在 40 dpi 时严重得多，在 53 dpi 时则严重得多。胎儿中枢神经系统病变包括局灶性小胶质细胞增生（伴或不伴中央坏死）、淋巴套囊和非化脓性脑膜炎。胎儿的肝脏、心脏和肺部也发现了病变。新孢子虫抗原在胎儿大脑和胎盘组织中得到证实，并在 25 dpi 时在胎儿肝脏和心脏的单个样本中得到证实。肩胛前淋巴结的大小与对照胎儿的淋巴结没有差异，但更成熟，因为它们含有明显更多数量的次级滤泡。在受感染母羊胎儿的血清中检测到了犬新孢子虫的 IgM 和 IgG 抗体。因此，犬新孢子虫很容易感染怀孕的母羊，并引起胎儿组织和胎盘的病变，类似于绵羊弓形体病。此外，其变化与牛新孢子虫病相似；因此，受感染的怀孕母羊为牛病提供了一个良好的模型。 (C) 1997 W.B.桑德斯有限公司。
In an initial experiment, 21 sheep in groups of five or six were inoculated subcutaneously (sc) with 10(8), 10(6) or 10(4) Neospora caninum tachyzoites (Liverpool isolate), or with control inoculum, and monitored for clinical signs and for ''seroconversion''. Animals given the two higher doses showed febrile responses and all three groups inoculated with the parasite showed seroconversion. In a second experiment, 12 pregnant sheep were each inoculated sc at 90 days' gestation with 10(6) tachyzoites, and at 25, 40 and 53 days post-inoculation (dpi) groups of four were killed for examination of the fetuses and placentas. Appropriate control ewes were included in the study. All fetuses were alive immediately before their darns were killed, except for one, which was found to be mummified at 40 dpi. Histopathological lesions were found consistently in both fetal central nervous system (CNS) and placental tissues. In the latter, focal necrosis, which was mild at 25 dpi, was much more severe al 40 dpi and much less severe at 53 dpi. Lesions in the fetal CNS consisted of focal microgliosis (with or without central necrosis), lymphoid cuffing and nonsuppurative meningitis. Lesions were also found in fetal liver, heart and lung. Neospora antigen was demonstrated in fetal brain and placental tissues and, at 25 dpi, in single samples of fetal liver and heart. The prescapular lymph nodes did not differ in size from those of control fetuses but were more mature in that they contained a significantly greater number of secondary follicles. Both IgM and IgG antibodies to N. caninum were detected in the serum of fetuses from infected ewes. Thus, N. caninum readily infected pregnant ewes and caused lesions in fetal tissues and placentas which resembled those of ovine toxoplasmosis. In addition, the changes were similar to those of bovine neosporosis; the infected pregnant ewe therefore offers a good model for the bovine disease. (C) 1997 W.B. Saunders Company Limited.