Identification and subsequent studies of foot-and-mouth disease virus

Foot-and-mouth disease virus, type A, strain 119, (FMDV-A 119) was purified from infectious tissue culture fluid, bovine vesicular fluid, and tongue epithelium and identified by analytical electron microscopy as a particle approximately 23 mμ in diameter. In addition, a smaller particle (8 ± 2 mμ) closely associated with the virus particle, particularly in animal-derived material, was found in centrifugally-separated fractions which possessed complement-fixing activity.