Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Vet Parasitol. 2012 Jun 8;187(1-2):72-8. doi: 10.1016/j.vetpar.2011.12.030. Epub 2011 Dec 30.
The aim of this study was to characterize the pathogenesis of Neospora caninum in experimentally inoculated pregnant water buffalo (Bubalus bubalis). Twelve Mediterranean female water buffaloes ranging in age from 4 to 14 years old and seronegative to N. caninum by indirect fluorescent antibody test (IFAT) were involved. Ten females were intravenously inoculated with 10(8) tachyzoites of NC-1 strain at 70 (n=3) or 90 (n=7) days of pregnancy (dp). Two control animals were inoculated with placebo at 70 and 90 dp, respectively. Serum samples were obtained weekly following inoculation to the end of the experiment. Three animals inoculated at 70 dp were slaughtered at 28 days post inoculation (dpi), three animals inoculated at 90 dp were slaughtered at 28 dpi and the remaining four animals inoculated at 90 dp were slaughtered at 42 dpi. Fetal fluids from cavities and tissue samples were recovered for IFAT and histopathology, immunohistochemistry and PCR, respectively. Genomic DNA from fetal tissues was used for parasite DNA detection and microsatellite genotyping in order to confirm the NC-1 specific-infection. Dams developed specific antibodies one week after the inoculation and serological titers did not decrease significantly to the end of the experiment. No abortions were recorded during the experimental time; however, one fetus from a dam inoculated at 70 dp was not viable at necropsy. Specific antibodies were detected in only two fetuses from dams inoculated at 90 dp that were slaughtered at 42 dpi. No macroscopic changes in the placentas and organs of viable fetuses were observed. Nonsuppurative placentitis was a common microscopic observation in Neospora-inoculated specimens. Microscopic fetal lesions included nonsuppurative peribronchiolar interstitial pneumonia, epicarditis and myocarditis, interstitial nephritis, myositis and periportal hepatitis. Positive IHC results were obtained in two fetuses from dams inoculated at 70 dp and slaughtered at 28 dpi. N. caninum DNA was detected in placentas and fetuses from all inoculated animals. The pattern of amplified microsatellites from placental and fetal tissues resembled the NC-1 strain. Water buffaloes, like cattle, are susceptible to experimental inoculation with N. caninum at early pregnancy.
本研究旨在探讨刚地弓形虫（Neospora caninum）在实验感染怀孕水牛（Bubalus bubalis）中的发病机制。共涉及 12 头年龄在 4 至 14 岁之间的地中海雌性水牛，间接荧光抗体试验（IFAT）检测均为 N. caninum 血清阴性。10 头水牛在怀孕 70（n=3）或 90 天（n=7）时经静脉接种 10（8）个 NC-1 株速殖子。2 头对照动物分别在 70 和 90 天接种安慰剂。接种后每周采集血清直至实验结束。3 头于 70 天接种的动物在接种后 28 天（dpi）屠宰，3 头于 90 天接种的动物在 28 dpi 屠宰，其余 4 头于 90 天接种的动物在 42 dpi 屠宰。分别采集腔液和组织样本进行 IFAT、组织病理学、免疫组织化学和 PCR。用胎儿组织基因组 DNA 进行寄生虫 DNA 检测和微卫星基因分型，以确认 NC-1 特异性感染。接种后一周，母畜产生特异性抗体，血清学效价在实验结束时未显著下降。实验期间未发生流产；然而，1 头于 70 天接种的母畜的胎儿在尸检时无活力。仅在 42 dpi 屠宰的 2 头于 90 天接种的母畜的 2 头胎儿中检测到特异性抗体。在有活力的胎儿的胎盘和器官中未观察到明显的宏观变化。非化脓性胎盘炎是 Neospora 接种标本的常见显微镜观察结果。显微镜下胎儿病变包括非化脓性细支气管间质性肺炎、心内膜炎和心肌炎、间质性肾炎、肌炎和门管区肝炎。在接种后 28 dpi 屠宰的 2 头于 70 天接种的母畜的胎儿中获得了阳性 IHC 结果。从所有接种动物的胎盘和胎儿中均检测到 N. caninum DNA。胎盘和胎儿组织中扩增微卫星的模式与 NC-1 株相似。水牛与牛一样，在怀孕早期易受实验性 N. caninum 接种感染。
