Which of the following is least likely to cause vesicular lesions in swine?

Rinderpest is primarily a viral disease that affects cattle and certain wild ungulates, not swine. While it is a significant disease in its host species, it does not cause vesicular lesions in pigs. Vesicular diseases in swine are typically associated with viral infections that directly affect them, such as swine vesicular disease and foot and mouth disease, both of which are known to cause these lesions.

Pigs housed on concrete would not inherently lead to vesicular lesions; instead, housing conditions may influence other aspects of animal health and welfare, such as stress or injury, but they do not directly cause viral diseases that result in vesicular lesions. Rinderpest being specific to other species makes it the least likely option to produce such lesions in swine.