Parasitological symbolism

I just finished writing the copy for the back cover of the new (8th) edition of FOUNDATIONS OF PARASITOLOGY. The 7th edition had a number of parasites and vectors assembled into a rather artistic montage, and so does the 8th edition, although with different organisms. The cover copy dealt with the symbolism of those parasites: what they brought to mind when I saw them. This experience makes me wonder what other parasites might be used in a similar fashion, and of course the answer is: all of them. Obviously some would be a stretch, in the sense that a whole lot of history, economics, sociology, and human-to-human interactions might not come immediately to mind when you see a picture of them, but others (Xenopsylla cheopis, for example) would release a flood of such material from a well educated parasitologist. I'd be interested in your contributions! - JJ