I had no idea how efficient those little fellas can be. I imagined that most of a parasite's wanderings through a host's body was all random; Zimmer elegantly describes how Fasciola hepatica's migration to the liver is as purposeful, focused, and orchestrated as any business trip that we might undertake.
Among the many jewels, he has brought to the public the fascinating speculation that Crohn's disease is a direct result of our freedom from parasites. His account of the impending eradication of guinea worm (possibly river blindness too) all makes for a great read. Its easy style and engaging facts make it hard to put down. True, sometimes I found Zimmer's proposals a little too far fetched-I really don't think he would convince many sheep farmers to let parasites control (decrease) their stocking density when they can easily do it themselves by simply selling some sheep.
Read Parasite Rex and you'll have a whole new appreciation of life as we know it. Zimmer will convince you that parasitism is an acceptable way to make a living-no mean feat!
Morgan Morrow
The author, Carl Zimmer, starts with a history of the oft misunderstood creatures (which range from viruses to animalian life and through many life stage forms). He then moves on to explaining life cycles of parasites and how they affect their environment (sometimes by controlling their hosts right down to their sex lives); he uses specific examples to do so with incredible and often gross detail. But the "gross factor" of this book is definintely part of the reason for reading it! This book is just plain fun. Zimmer also posits some theories on how to use parasites to our advantage (among other things) which sound outlandish or impractical, but are interesting and thought provoking nonetheless. Pictures and a glossary of terms are included to add to your education in parasitology.
This is easily one of the best science books of the last year. It is thorough without being difficult to read or too academic for the layperson. As well as being an engrossing read, it also is fun, gross and creepy -- just the thing to keep you up at night and make you start to pay more attention to your world. Read this book!
I had a dream one night before going to the dentist. I dreamed that there were scores of little white noodles like spaghetti coming out of my gums and tongue when I pressed them. Initially I thought this was a dream of the grooming instinct. But after reading Carl Zimmer's creepy but utterly fascinating book, I believe this primeval dream may have been a dream of parasites.
In a sense this is the scariest book I have ever read. I had to put it aside twice because the horror depicted on its pages was affecting my usually buoyant state of mind. Make no mistake about it, however objectively we may try to view our fellow creatures, it is impossible (at least for me) to see parasites as anything other than ugly and despicable. (I'm working on it, however.)
But Zimmer has an important purpose in writing this book aside from scaring us. He makes it clear that we cannot understand how an ecology works without understanding the role parasites play in that ecology. For example on page 111 we have wolves choosing to attack a moose that is slow and wheezing, a moose riddled with tapeworms, tapeworms seeking their final host, the wolf! The wolves are led to choose the infected moose perhaps by a scent in the moose's breath, created by the tapeworms. "The thinning of the herd is an illusion, not the service of the predator but the side effect of a tapeworm traveling through its life."
In Chapter 3, "The Thirty Years' War," Zimmer shows how the immune system fights against parasites. It is an excellent exposition on how the immune system works, and one of the highlights of the book. In the chapter "Evolution from Within," we see parasites as a driving force in evolution. The idea that sexuality began as a way to fight disease, the so-called "Red Queen" hypothesis is presented. Zimmer shows how being different instead of a clone of the mother (asexual reproduction) can lead to characteristics that foil parasites. There are sixteen pages of glossy photos of parasites, several showing the grotesque heads of tapeworms in intimate detail. There are photos of a crustacean parasite that invades a fish's mouth, eats its tongue and then takes the place of the tongue.
A question that might be asked is, what is a parasite? Certainly in biology a parasite is different than a symbiont, which is distinguished from a predator, etc. Zimmer gives Richard Dawkins's definition that "Parasitism is any arrangement in which one set of DNA is replicated with the help of--and at the expense of--another set of DNA" (p. 126). By this definition perhaps humans are parasites on Planet Gaia. Zimmer suggests as much on page 245 adding that "There's no shame in being a parasite...But we are clumsy in the parasitic way of life." He explains that expert parasites do no more harm than is necessary. "If Gaia had an immune system, it might be disease and famine" to keep "an exploding species from taking over the world. But we have dodged these safeguards with medicines and toilets and other safeguards..."
Zimmer ends the book on a rather cheery note: parasites as the canary in the coal mine. He argues that parasites are not only an indication of ecological health (plenty of parasites suggests a healthy ecosystem; a drop in their numbers suggests trouble, perhaps from pollution), but are vital to the ecology by keeping animal populations in check (pp. 241-243). He also gives some idea of how parasites might benefit us more directly, such as a fungus that invades insects as "the source of cyclosporin, an important antibiotic" or the use of blood-clotting molecules produced by hookworms as blood thinners in surgery (p. 238). Although there have been failures in the use of parasites to control insect populations, and Zimmer recounts two or three, there is also the story of how a parasitic wasp imported from South America saved the African cassava crop from mealybugs (pp. 220-228).
As others have noted, reading this book will forever change the way you view the natural world, and might make you cancel that trip to the tropics.
