56410University of Pretoria, Onderstepoort, Pretoria, South Africa.
5308Kansas State University, Manhattan, KS, USA.
Vet Pathol. 2020 Nov;57(6):791-806. doi: 10.1177/0300985820954549. Epub 2020 Sep 4.
Infection with (RVFV) causes abortion storms and a wide variety of outcomes for both ewes and fetuses. Sheep fetuses and placenta specimens were examined during the 2010-2011 River Valley fever (RVF) outbreak in South Africa. A total of 72 fetuses were studied of which 58 were confirmed positive for RVF. Placenta specimens were available for 35 cases. Macroscopic lesions in fetuses were nonspecific and included marked edema and occasional hemorrhages in visceral organs. Microscopically, multifocal hepatic necrosis was present in 48 of 58 cases, and apoptotic bodies, foci of liquefactive hepatic necrosis (primary foci), and eosinophilic intranuclear inclusions in hepatocytes were useful diagnostic features. Lymphocytolysis was present in all lymphoid organs examined with the exception of thymus and Peyer's patches, and pyknosis or karyorrhexis was often present in renal glomeruli. The most significant histologic lesion in the placenta was necrosis of trophoblasts and endothelial cells in the cotyledonary and intercotyledonary chorioallantois. Immunolabeling for RVFV was most consistent in trophoblasts of the cotyledon or caruncle. Other antigen-positive cells included hepatocytes, renal tubular epithelial, juxtaglomerular and extraglomerular mesangial cells, vascular smooth muscle, endothelial and adrenocortical cells, cardiomyocytes, Purkinje fibers, and macrophages. Fetal organ samples for diagnosis must minimally include liver, kidney, and spleen. From the placenta, the minimum recommended specimens for histopathology include the cotyledonary units and caruncles from the endometrium, if available. The diagnostic investigation of abortion in endemic areas should always include routine testing for RVFV, and a diagnosis during interepidemic periods might be missed if only limited specimens are available for examination.
（RVFV）感染可导致母羊流产和胎儿出现多种不同结局。在南非 2010-2011 年河谷热（RVF）爆发期间，对绵羊胎儿和胎盘标本进行了检查。共研究了 72 个胎儿，其中 58 个经证实为 RVFV 阳性。35 个病例有胎盘标本。胎儿的大体病变是非特异性的，包括内脏器官明显水肿和偶尔出血。显微镜下，48 例 58 例存在多灶性肝坏死，凋亡小体、液化性肝坏死（原发性灶）和嗜酸性核内包涵体是有用的诊断特征。除胸腺和派伊尔斑外，所有检查的淋巴器官均存在淋巴细胞溶解，肾肾小球常有核固缩或核碎裂。胎盘中最重要的组织学病变是绒毛膜和绒毛膜绒毛的滋养层和内皮细胞坏死。RVFV 的免疫标记在胎盘中最一致的是胎盘中的滋养层或肉阜。其他抗原阳性细胞包括肝细胞、肾小管上皮细胞、肾小球旁器和外系膜细胞、血管平滑肌、内皮细胞和肾上腺皮质细胞、心肌细胞、浦肯野纤维和巨噬细胞。用于诊断的胎儿器官样本至少应包括肝脏、肾脏和脾脏。从胎盘来看，如果有子宫内膜，建议对绒毛膜绒毛的绒毛小叶和肉阜进行组织病理学检查。在流行地区，对流产的诊断性调查应始终包括 RVFV 的常规检测，如果仅检查有限的标本，可能会错过流行间期的诊断。
