This experiment allows learners to experience a small scale "epidemic," demonstrating the ease with which disease organisms are spread, and enables learners to determine the originator of the "epidemic." Learners will transfer live bacteria by hand contact, then transfer an inoculum to a nutrient agar plate for 24 hour incubation. After incubation, plates are observed for growth of the microbial agent. By arranging the plates in the order of hand contact, it can be determined which individual received the original contaminant and started the "epidemic," which individuals transferred the organism yet did not grow it out (carriers), and how dosage, or amount of contamination, affects getting a disease. Other means of microbial transmission (air, water, body fluids, fomites) may also be discussed. This lesson guide includes safety precautions, questions, and an additional activity to simulate vaccination.