Alexandersen Soren, Oleksiewicz Martin B, Donaldson Alex I
Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK1.
J Gen Virol. 2001 Apr;82(Pt 4):747-755. doi: 10.1099/0022-1317-82-4-747.
Foot-and-mouth disease (FMD) is a highly contagious, economically important virus disease of cloven-hoofed animals. The objective of the present study was to examine the early pathogenesis of FMD in pigs by a quantitative time-course study. Under experimental conditions, recipient pigs were infected by contact with donor pigs affected by FMD. Every 24 h from day 1 to day 4 after exposure, two recipient pigs were selected randomly, killed and necropsied. A range of tissues were analysed by a quantitative TaqMan RT-PCR method and by titration of FMD virus on primary bovine thyroid cells. The titres of virus determined by assay in cell culture and calculated from the quantitative TaqMan data correlated strongly (r>0.9), thereby establishing the validity of the TaqMan calculations. The data indicated that the replication of virus in the lungs contributes only in small part to airborne virus excretion. Sites in the pharynx, trachea and nasal mucosa are probably more important in that regard. The sites of earliest virus infection and possibly replication in recipient pigs appeared to be in the pharynx (soft palate, tonsil and floor of pharynx). The data indicated that FMD virus replication in pigs is rapid and that the majority of virus amplification occurs in the skin. A model for the progression of infection is proposed, indicating initial spread from the pharyngeal region, through regional lymph nodes and via the blood to epithelial cells, resulting in several cycles of virus amplification and spread.
口蹄疫（FMD）是一种偶蹄动物高度传染性、具有重要经济影响的病毒性疾病。本研究的目的是通过定量时间进程研究来检测猪口蹄疫的早期发病机制。在实验条件下，受体猪通过与感染口蹄疫的供体猪接触而被感染。在接触后的第1天至第4天，每隔24小时随机选择两只受体猪，宰杀并进行尸检。通过定量TaqMan RT-PCR方法以及在原代牛甲状腺细胞上对口蹄疫病毒进行滴定，对一系列组织进行分析。通过细胞培养测定法确定的病毒滴度与根据定量TaqMan数据计算得出的滴度高度相关（r>0.9），从而证实了TaqMan计算的有效性。数据表明，病毒在肺部的复制对口蹄疫病毒的空气传播排泄贡献较小。在这方面，咽部、气管和鼻黏膜的部位可能更为重要。受体猪中最早的病毒感染部位以及可能的复制部位似乎在咽部（软腭、扁桃体和咽底部）。数据表明，口蹄疫病毒在猪体内的复制迅速，且大部分病毒扩增发生在皮肤。提出了一个感染进展模型，表明感染最初从咽部区域开始传播，通过局部淋巴结并经血液传播到上皮细胞，导致病毒扩增和传播的多个循环。
