The Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Who We Are Today

“Grabbing the reader from the start with a brief introduction to human evolution and anthropology, author Dunn moves through the answer to these and other questions with a sure use of language, scientific research, and humor—all of which combined keep the reader highly engaged.”

The Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Who We Are Today by Rob Dunn explores several evolutionary questions, the answers to which are not immediately obvious:

• What good can worms do for Crohn’s disease, asthma, and other autoimmune diseases?
• What does the appendix do?
• How did cows domesticate humans?
• Why did humans lose the vast majority of their body hair?
• What do snakes have to do with the development of acute vision?

Grabbing the reader from the start with a brief introduction to human evolution and anthropology, author Dunn moves through the answer to these and other questions with a sure use of language, scientific research, and humor—all of which combined keep the reader highly engaged.

For example, Mr. Dunn discusses the hygiene hypothesis, which proposes that in the developed world the recent predisposition with antibacterial products and the eradication of germs can actually be harmful: With nothing to fight, the theory goes, the body begins to turn against itself in the form of allergies, asthma, and autoimmune diseases. Mr. Dunn proposes that evolutionarily, humans typically had symbiotic parasites (worms or other organisms that benefit their host, while deriving benefits from living inside the host’s system), as may be seen in developing countries. In more modern times and in developed countries humans do not play host to these organisms; however, our physiology has not yet adapted to this cleaner state of living, and without the help of worms that help us digest foreign bodies and keep our immune system from being overactive, the body’s immune system doesn’t have anything left to fight with.

With this in mind, Mr. Dunn guides us through several stories of people who have safely and temporarily “repopulated” their intestines with hookworms or other parasites. If we have not yet adapted to having parasite-free digestive systems, he argues, and we develop a debilitating autoimmune digestive disorder such as Crohn’s disease, then allowing hookworms to have temporary access to our digestion may alleviate some of the causes of this disease: an overactive immune system that has turned on itself. Repopulation with hookworms may “turn down” this immune reaction and restore the normal immune equilibrium.

Indeed, this is what Mr. Dunn describes. Although this seems to be a highly promising approach, several practical things must still be considered, including what types of worms should be used, where it is performed, how the worms are processed, and how long they are allowed to remain in the body. With luck, such approaches will be evaluated in future, particularly for people who suffer from diseases that otherwise prevent them from living a happy and fulfilled daily life.

The use of worms to alleviate immune and other disorders is only one part of the fascinating discussion in The Wild Life. Mr. Dunn is a thorough and talented writer, and his genuine interest in the material he covers in this book is conveyed to the reader through his clear language, well-researched studies, and the unification of both modern man and his evolutionary history. The reader, whether seriously into science or just dipping in a curious toe, will be impressed and stimulated by Mr. Dunn’s thoughtful discussions and academic expertise.