Multiple choice Which of the following pathogens was not discovered by Robert Koch? Mycobacterium tuberculosis Mycobacterium leprae Bacillus anthracis Vibrio cholerae Reveal answer Fill a bubble to check yourself B Correct answer Explanation Gerhard Henrik Armauer Hansen discovered Mycobacterium leprae in 1873. This was the first time that a chronic infectious disease in humans was shown to be related to a bacillus.