@Michael Rupp "Parasites" and "bacteria" only contrast in the parlance of clinical labs where "parasites" tend to denote ...single- or many-celled animals in your digestive tract evidenced through the analysis of feces. Koch's bacillus is definitely not an animal and definitely a bacterium.
What I don't understand is what prompted your question in the context.
I've heard of parasites that have the property of making the host change behavior in a way that benefits the parasite. Like a cat has a parasite present in it's fecal matter that if a rodent gets exposed will become sexually attracted to cat's who eat the rodent and the cycle of the parasites life continues. I might have that wrong. 8(
e.g. the Koch parasite has convinced people with little power to give more power to the Koch's who are taking it away from them.