Cholera is an infectious disease caused by bacteria named Vibrio cholerae. Cholera causes profuse diarrhea episodes and vomiting. The cause of cholera are toxins secreted by the Vibrio cholerae bacteria.Microscopically, these bacteria appear curved (comma-shaped) and have a negative Gram stain.holera causes profuse diarrhea episodes and vomiting. The cause of cholera are toxins secreted by the Vibrio cholerae bacteria. Microscopically, these bacteria appear curved (comma-shaped) and have a negative Gram stain.