Localization of foot-and-mouth disease virus RNA by in situ hybridization within bovine tissues

Foot-and-mouth disease is a highly contagious disease of cloven hooved anim als. In cattle, both acute and long-term persistent infections occur. Foot- and-mouth disease virus (FMDV), a picornavirus, has been shown, using virus isolation procedures, to replicate in the pharynx and soft palate of cattl e. In this study, in situ hybridization has been used to detect FMDV RNA wi thin the cells of tissues removed from infected bovines. A digoxigenin-labe lled anti-sense RNA probe was prepared corresponding to a region of the FMD V genome encoding part of the RNA-dependent RNA polymerase (3D). The effica cy and specificity of this probe for in situ hybridisation was determined u sing virus-infected cells in tissue culture. Strong cytoplasmic staining wa s only detected in FMDV-infected cells. Various tissue samples were collect ed from FMDV-infected cattle between 5 and 17 days post-infection. Viral RN A was detected by in situ hybridisation within cells of the soft palate, to nsil and pharynx up to 17 days post-infection. This technique is useful for the study of FMDV localization in cattle both during and after the acute c linical phase of disease and may assist in identifying specific sites of vi rus persistence. (C) 1999 Elsevier Science B.V. All rights reserved.