Most American\'s are immune to the bacterium that causes Leprosy, does that mean that most American\'s are also, immune to TB and Crohn\'s disease? Or are the different strands of myobacterium much more contagious and less easy to fight off? Pathophysiciology Course question Solution 9. Leprosy Transmitted by nasal droplets. Leprosy occurs during close contact with those who are infected 10. TB can spread when patient cough, sneeze, speak, sing, or spit, they expel infectious aerosol droplets.