MacLachlan N J, Conley A J, Kennedy P C
Departments of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis 95616, USA.
Anim Reprod Sci. 2000 Jul 2;60-61:643-51. doi: 10.1016/s0378-4320(00)00105-6.
A number of viruses have the capacity to cross the placenta and infect the fetus to cause, among other potential outcomes, developmental defects (teratogenesis), fetal death and abortion. Bluetongue virus (BTV) infection of fetal ruminants provides an excellent model for the study of virus-induced teratogenesis. This model has shown that only viruses modified by passage in cell culture, such as modified live virus vaccine strains, readily cross the ruminant placenta, and that the timing of fetal infection determines the outcome. Thus, cerebral malformations only occur after fetal infection at critical stages during development and the precise timing of fetal BTV infection determines the severity of the malformation present at birth. Fetal BTV infection also can result in fetal death, followed by abortion or resorption, growth retardation, or no obvious abnormalities, depending on age of the conceptus at infection. Equine arteritis virus (EAV) infection of the equine fetus causes fetal death and abortion but not teratogenesis. These two fetal viral infections are useful not only for the study of teratogenesis and fetal disease, but also to further characterize and compare the complex process that is responsible for normal induction of parturition in ruminants and horses.
许多病毒能够穿过胎盘并感染胎儿，从而导致发育缺陷（致畸作用）、胎儿死亡和流产等一系列潜在后果。胎儿反刍动物感染蓝舌病病毒（BTV）为研究病毒诱导的致畸作用提供了一个极佳的模型。该模型表明，只有经过细胞培养传代修饰的病毒，如减毒活疫苗株，才能轻易穿过反刍动物的胎盘，而且胎儿感染的时机决定了结果。因此，脑部畸形仅在发育关键阶段的胎儿感染后出现，胎儿感染BTV的精确时机决定了出生时畸形的严重程度。胎儿感染BTV还可能导致胎儿死亡，随后出现流产或吸收、生长发育迟缓，或者根据感染时孕体的年龄没有明显异常。马胎儿感染马动脉炎病毒（EAV）会导致胎儿死亡和流产，但不会致畸。这两种胎儿病毒感染不仅有助于研究致畸作用和胎儿疾病，还能进一步表征和比较反刍动物和马正常诱导分娩的复杂过程。
