Question

An epidemic has spread through the UH Hilo undergraduate student body that is currently living on campus. Many of the cases of students (sick) do NOT seem to be living off campus and eat regularly at the cafeteria. Symptoms are muscle weakness, loss of facial expression and trouble eating and drinking. It seems as if the cafeteria is the source (food-born) of the illness, but the campus administrators are not sure what to do next! However, since you have just about completed Biol375, you understand the immune system and epidemiology quite well. (Questions 1-5)

1. (20 pts) The campus health officials cannot figure out source of the problem. The students are blaming the cafeteria, BUT the cafeteria workers have all been trained in food handling procedures and have not had a case of E. coli or Salmonella outbreak in years. Explain what epidemiology is and how it can be used in this epidemic case.

2. (20pts) The health officials on campus are close to solving the outbreak source and have narrowed down the two suspects: Clostridium tetani and Clostridium botulinum. As a consultant you quickly identify the pathogen that is causing the problems as _____________? Explain your choice by explaining WHY the symptoms in the students match your answer AND why the other choice is incorrect. (Hint: you may want to draw pictures (& label) of the virulence factors and its mode of action.)

3. (20 pts) If the pathogen Clostridium is exposed to a person, how do our innate immune defenses work to try to eliminate the foreign invader? (Make sure to name a few innate immune defense, and not just 2!)

4. (20 pts) If the pathogen Clostridium is exposed to a person AND is able to get through our nonspecific defenses (innate defenses), how do our adaptive immune defenses work to try to eliminate the foreign invader? Answer question by explaining how cytotoxic T cells mediate the immune response against C. botulinum

5. (20 pts) If the Clostridium pathogen is exposed to a person AND is able to get through our nonspecific defenses (innate defenses), how do our adaptive immune defenses work to try to eliminate the foreign invader? Answer question by explaining how T helper cells mediate the immune response against C. botulinum.

Answer 1

Botulism is a rare and potentially fatal illness caused by a toxin produced by the bacterium Clostridium botulinum. Botulinum neurotoxin reaches nerve terminals at the neuromuscular junction, where it binds to the neuronal membrane, moves into the cytoplasm of the axon terminal, and acts to block excitatory synaptic transmission, leading to flaccid paralysis The toxin blocks the release of acetylcholine but not its synthesis or storage as it is shown in a diagram in one of the picture above.