Wednesday, August 20, 2008
Textbook cover copy
FOUNDATIONS OF PARASITOLOGY cover art suggests the diversity of parasitic organisms, the historical significance of parasitic diseases, and the often-complicated relationships involving parasites. Snails are first intermediate hosts for virtually all trematodes, whose life cycles are dependent on intact food webs and other ecological interactions. Biomphalaria glabrata, the cover’s central figure, is a New World snail vector for schistosomiasis, one of humanity’s major parasitic afflictions, and one that also is linked closely to agricultural practices. As is the case with many parasites, an understanding of the role played by intermediate hosts such as B. glabrata is crucial to any control efforts. The bedbug, Cimex hemipterus, represents a pest whose global importance is increasing, probably due to insecticide resistance, thus reminding us that many, and some believe most, parasites have the potential for evolving defenses against compounds traditionally used to control them. The beautiful Giardia agilis, from amphibians, reminds us that our own parasites, e.g., Giardia duodenalis, often are part of a larger spectrum of related species. The aspidobothrean Cotylaspsis insignis appears highly magnified, but faint in the background, almost as if important but remembered from a distant past. Such imagery is valid; the bibliography of those who’ve worked on aspidobothreans reads almost like a historical record of parasitology. Finally, the sunfish, a common denizen of fresh waters, is both intermediate and definitive host for dozens of parasites, a reminder that parasitism is the most common way of life: every free-living species that has been studied extensively has been shown to be infected, usually with multiple other species.