Possible Clues:

• Any disease-producing agent
• Disease-causing agent
• Disease-causing organism – track oxygen data
• Greedy type tucking into plate — it may make him sick
• Way old dope becomes cause of illness
• What's spread around pig? Name source of disease
• Bacterium, possibly from pig, kept in dish
• Gone off course before finding cause of illness
• Disease-causing micro-organism
• Pig in dish - it may make one sick