Antiviral activity of rS. cho in swine. Animals were treated with saline (A), S. cho (B), pLacZ/S. cho (C), p3D-NT56/S. cho (D), or a high dose of p3D-NT56/S. cho (E) and challenged as described in the Materials and Methods section. After challenge, lesion scores were assigned to the animals according to the number of digits plus mouth with vesicles.